Skip to main content
[email protected]WhatsApp : +91 91063 65667Open Access Journal|Peer-Reviewed|Multidisciplinary|Research for a Better Tomorrow.ISSN 2984-8911ESTD 2023
JMVRA logoJMVRA – ISSN 2984-8911Journal of Modern and Versatile Research ApproachPeer ReviewedESTD 2023Open AccessCrossref DOI Submit Paper

JMVRA Home Journal Blog Journal Publisher Guide

Journal Publisher Guide · Journey & Wisdom

How to Get an ISSN for Your Journal: Complete 2026 Guide

An ISSN is the first identifier every new journal needs, and in India it is issued free of charge by the ISSN National Centre at CSIR-NIScPR. This guide walks you through eligibility, the first-issue rules, the documents and website pages the Centre checks, the real timeline, and what to do once the number is assigned.

TypeComplete Guide Reading time22 min Updated16 Oct 2026 ByJMVRA Editorial Team
FreeISSN fee at the National Centre, India
30+working days minimum processing
5articles minimum in first online issue
5editorial board members minimum

What Is an ISSN and Why Every Journal Needs One

If you are wondering how to get an ISSN for a journal, start with what the number actually is. The International Standard Serial Number (ISSN) is an eight-digit code, defined by the international standard ISO 3297, that identifies a serial publication: a journal, magazine, newspaper, annual report or monographic series that is published in successive parts with no planned end. It is written as two groups of four digits separated by a hyphen, for example ISSN 2984-8911, which is the online ISSN of JMVRA (Journal of Modern and Versatile Research Approach).

The ISSN identifies the title in a specific medium. It does not identify a single article (that is the job of a DOI) and it says nothing about quality. The ISSN National Centre for India states this plainly: assigning an ISSN does not amount to approving a journal or its contents. Any journal that writes "approved by NSL" or "approved by NIScPR" next to its ISSN is misusing the number.

Why the ISSN still matters

1

Unique identity

Two journals can share a similar name; they can never share an ISSN. Libraries, databases and citation tools use it to tell titles apart.

2

Prerequisite for next steps

DOI registration, discovery services and most indexing applications expect a confirmed ISSN record before they look at your journal.

3

Author confidence

Authors and their institutions check the ISSN on the ISSN Portal to confirm the journal is a real, registered serial.

4

Library and subscription systems

Acquisition, cataloguing and link-resolver systems are keyed on the ISSN, so a missing or wrong number breaks access.

How the check digit works

The eighth character is a check digit calculated from the first seven using modulus 11. Multiply the seven digits by the weights 8, 7, 6, 5, 4, 3 and 2, add the results, divide by 11 and subtract the remainder from 11. A result of 10 is written as the letter X, and a remainder of 0 gives a check digit of 0. For 2984-8911: (2×8) + (9×7) + (8×6) + (4×5) + (8×4) + (9×3) + (1×2) = 208. 208 divided by 11 leaves a remainder of 10, and 11 − 10 = 1, which matches the final digit. This is why you can never invent or "reserve" an ISSN yourself: only an ISSN centre assigns valid, registered numbers.

ISSN vs ISBN vs DOI: Which Identifier Does What

New publishers often mix up the three identifiers. Each one answers a different question, and a well-run journal usually ends up with an ISSN for the title and a DOI for every article.

The three identifiers compared
FeatureISSNISBNDOI
IdentifiesA serial title in one mediumOne edition and format of a bookAn individual object: article, chapter, dataset
Format8 digits (XXXX-XXXX)13 digits (978/979 prefix)Prefix/suffix, e.g. 10.xxxxx/abc
Issued in India byISSN National Centre, NSL, CSIR-NIScPRRaja Rammohun Roy National Agency for ISBNA registration agency such as Crossref, via membership or a sponsor
Cost in IndiaFreeFreeMembership and per-record fees (or a sponsor's charges)
Resolves to a web page?No, it is a catalogue identifierNoYes, through doi.org
Can a journal use it?YesNo (books only)Yes, for each article
Common mistake: Applying for an ISBN for a journal or an ISSN for a single book. The Indian ISSN guidelines say books are not eligible for an ISSN; the correct identifier for a book is the ISBN, issued through isbn.gov.in.

Who Issues ISSNs: International Centre, National Centres and the ISSN Portal

The ISSN system is run by a network. The ISSN International Centre in Paris maintains the ISSN Register and publishes it through the ISSN Portal (portal.issn.org). National centres in member countries assign numbers for serials published in their country and send the records to the International Centre.

  1. Publisherapplies to the national centre of the country of publication
  2. National centrechecks the title, assigns the ISSN, creates the record
  3. ISSN International Centrevalidates and adds the record to the ISSN Register
  4. ISSN Portalthe confirmed record becomes publicly searchable

The ISSN National Centre for India

For serials published from India, the national centre is the ISSN National Centre at the National Science Library (NSL), CSIR-National Institute of Science Communication and Policy Research (CSIR-NIScPR), New Delhi. Its portal is the NSL ISSN process page, which links to the online application, application status, ISSN search, guidelines and FAQs. According to that page, the Centre assigned 1,181 ISSNs in 2025 and 27,777 between 1986 and 2025.

No agents: The National Centre states that it has no agents or brokers and that the ISSN is free. Consultants who charge for "ISSN registration" are charging for form-filling help, not for the number, and they cannot speed up or guarantee approval.

Which country's centre do you apply to?

The rule is the country of publication, that is, where the publisher is located, not where the editors or authors live. An Indian publisher applies in India even if the journal is international in scope. A publisher in a country without a national centre applies through the ISSN International Centre's online publisher area; the International Centre charges for that service, so check the current fee on the ISSN request page at issn.org.

ISSN Eligibility in India: What the National Centre Checks

Most rejected applications fail on eligibility, not paperwork. The current guidelines of the ISSN National Centre for India (revised in 2025) set out conditions that go beyond "you publish a journal". Read them as a quality floor your journal must clear before you apply.

Rules for online journals

  • No ISSN is assigned ahead of publication. The first issue must be released online first.
  • The first issue must be a real, complete issue: at least 5 articles for a non-annual e-journal and at least 10 articles for an annual publication. Otherwise the assignment is deferred.
  • At least five editorial board members, displayed on the website with designation, department, institution, full address and official or institutional email addresses.
  • Full publisher name and contact address shown on the website.
  • A valid URL, with the journal covering a precise subject or addressing a specific target audience.
  • Each article separately hyperlinked; uploading only one PDF of the whole issue should be avoided.
  • Journals of an institution or organisation should be linked from that institution's website.

Rules for print journals

  • An ISSN can be requested before the first issue only with full information and an advanced mock-up, and not more than one month before release.
  • The record is not formally registered until the Centre receives proof of publication; send a copy of the first issue as soon as it is released.
  • The first issue should include the title page, editorial page and a minimum of 5–6 original articles (10 for annual publications).
  • Scientific, technical and academic journals do not need RNI (Press Registrar General) registration to get a print ISSN, per the guidelines' reading of the Press and Registration of Periodicals Act, 2023.

Editorial board standards

The guidelines ask for senior faculty on the boards of scholarly journals and advise against listing students or research fellows. If you call the journal "international", the board itself must be international, with some members from reputed institutions abroad. Personal webmail addresses (Gmail, Yahoo and similar) should be avoided in favour of institutional ones. Get written consent from every member before you list them; the Centre may decline an ISSN when misleading information about the editorial board is displayed.

Integrity conditions

The Centre reserves the right to decline an ISSN if plagiarised articles are found, if articles are reproduced from other publications (including conference proceedings), or if the publication shows misleading information about its address, editorial board, indexing, preservation arrangements or authorship. It can also revoke an ISSN later if such information comes to light.

An ISSN application is really an audit of your website: the Centre checks what a reader can see, so fix the site before you fill in the form.

ISSN Application Documents and Website Pages to Prepare

The online form is short. The work is in having the evidence ready. Prepare the following before you open the application.

Documents to keep ready

  • The online application, filled carefully, and the signed print copy of the form, which the guidelines ask you to submit with the enclosures
  • Self-attested address proof of the publisher: Aadhaar card, Voter ID, driving licence or passport
  • For print: the complete first issue, or the cover, title page, editorial page and at least 5–6 original articles; the editorial page must show editors' affiliations
  • For online: the journal URL; for subscription journals, a temporary user ID and password
  • Institutional authority letter, if the journal belongs to a college, university or society (good practice)

Website pages to publish first

  • Home page with the exact journal title, medium, frequency and publisher
  • About / Aims and Scope with a precise subject area and audience
  • Editorial board with full details of at least five members
  • Current issue with each article on its own page and its own PDF link
  • Contact page with the publisher's full postal address in India
  • Peer review, ethics, copyright and licensing policies

Get the title right before you apply

Search the Indian ISSN database on the NSL site and the ISSN Portal for your proposed title. The guidelines tell applicants to do this to avoid duplication. Make sure the title is identical everywhere: website header, article PDFs, the form, the masthead. A journal whose website says one name and whose PDFs say another invites a rejection. If you are still choosing a name, see our guide to choosing a journal name before you build the site.

A journal management system such as JWJMS gives you the submission portal, author dashboard, desk screening and issue-building workflow, so the first issue that the Centre reviews already comes from a documented editorial process rather than an email inbox.

How to Get an ISSN Number in India: Application Process

Here is the practical sequence for an Indian online journal. Print journals follow the same order, except that the application can go in up to one month before the first issue with a full mock-up.

  1. Publish issue 15+ original, peer-reviewed articles, each with its own page
  2. Audit the websitetitle, board, address, policies, article links
  3. Apply onlineNSL ISSN portal, form for the correct medium
  4. Send the signed copywith address proof and enclosures
  5. Track statusApplication Status page; answer queries quickly
  6. Confirm on ISSN Portalthen request the certificate

Filling in the form

The form asks for details such as the exact title, medium, frequency, starting year, subject, publisher name and address, and the URL for online titles. A few rules prevent most problems:

  • Use the title exactly as it appears on the publication. Do not add the abbreviation unless it is part of the title.
  • Give the publisher's real postal address in India, matching the address proof and the website.
  • State the frequency you can actually sustain. Monthly, quarterly, bi-annual and annual are all acceptable; missing your declared frequency later damages credibility with indexers.
  • Apply for one medium per application. If you need print and online, submit two applications.
  • After submitting, download the filled application from the Application Status tab, sign it and send it with the enclosures as the guidelines instruct.
Tip: Before you press submit, open your website in a private browser window and check every page an examiner would click: board, issue, articles, contact. Broken links or "coming soon" pages are the fastest route to a deferral.

Responding to queries

If the Centre asks for corrections, reply with the change made on the live website, not just a promise. Note that once an application is rejected or declined, the guidelines require a fresh application with all documents, so it pays to get the first one right.

ISSN Processing Time and Fees

The ISSN is free in India. The guidelines state that the request process may take a minimum of 30 working days, longer if information is missing or if many titles are involved. Plan your launch around that.

FreeISSN assignment by the Indian National Centre
30+working days minimum, per the guidelines
1 monthearliest pre-release request for print
0agents or brokers authorised by the Centre

A realistic launch timeline

  1. Months 1–2

    Define scope and title, recruit and confirm the editorial board, write policies, set up the website and submission system.

  2. Months 2–4

    Run the call for papers, screen and peer review submissions, and edit and typeset accepted papers.

  3. Month 4

    Publish the first issue online with at least five original articles, each on its own landing page.

  4. Month 4–5

    Audit the site and submit the ISSN application with the signed copy and address proof.

  5. Month 5–7 (general range)

    Processing of at least 30 working days, plus any query rounds. Keep publishing the next issue on schedule.

  6. After assignment

    Display the ISSN, check the ISSN Portal record, request the certificate and move on to DOI registration.

The months above are a general planning range, not an official schedule. Your timeline depends mainly on how fast you can attract and review enough good papers for a complete first issue.

Why ISSN Applications Are Rejected or Deferred

The National Centre can reject incomplete or inaccurate forms summarily. The reasons below come straight from the conditions in the guidelines, and every one is avoidable.

  • Applying for an online ISSN before the first issue is published
  • A first issue with too few articles (fewer than 5, or fewer than 10 for an annual title)
  • Fewer than five editorial board members, or members listed without full affiliation and institutional email
  • Students or research fellows on the board of a scholarly journal, or an "international" journal with an all-local board
  • Board members listed without their consent
  • Claims of indexing, impact factors or approvals that cannot be verified
  • Missing or non-Indian publisher address, or an address that does not match the proof
  • Plagiarised or previously published articles, including recycled conference papers
  • One combined PDF for the whole issue instead of separately linked articles
  • Title on the website differs from the title on the form or the PDFs
  • Using the online ISSN on print copies, or the reverse
Misleading claims cost you later too: The Centre reserves the right to revoke an ISSN if misleading information comes to light after assignment. Remove any "indexed in" logo you cannot prove, and never present the ISSN itself as an approval.

Run every article in the first issue through a similarity check before publication. A tool such as JWSCAN, which uses iThenticate similarity detection and gives an overall similarity index with a source-by-source report, helps the editor catch recycled text before the Centre does.

Getting an ISSN Outside India

The principles are the same worldwide (one ISSN per title per medium, the ISSN identifies, it does not endorse), but procedures and fees are set nationally.

Where to apply, by publisher location
Publisher located inApply toFee
IndiaISSN National Centre, NSL, CSIR-NIScPR, New DelhiFree
A country with a national ISSN centreThat country's national centre (listed on issn.org)Set by the national centre; many are free
A country without a national centreISSN International Centre, through its online publisher areaCharged; see issn.org for the current amount
International organisations (Yearbook of International Organizations, sections A–F)ISSN International CentreSee issn.org

A journal does not get a "more international" ISSN by applying abroad. If your publisher entity is in India, the Indian centre is the right one. International reach comes from your editorial board, author base, peer review and discoverability, not from where the ISSN was assigned.

After You Get an ISSN: Display, Certificate and Next Steps

Assignment is the start, not the finish. These steps protect the number and turn it into visibility.

1

Display it correctly

Show "ISSN XXXX-XXXX (Online)" on the website header or footer, every issue page and every article PDF. Use the right number for each medium.

2

Check the ISSN Portal

Search your title on portal.issn.org. JMVRA's record, for example, is at portal.issn.org/resource/ISSN/2984-8911. Link to your own record from the About page.

3

Request the certificate

The Indian Centre issues the ISSN Registration Certificate only after the record is confirmed on the international portal, so check that first, then use the certificate form on the NSL page.

4

Send validation copies

The guidelines warn that if the validation copy is not submitted after assignment, ISSNs for the publisher's new journals will be denied.

5

Register DOIs

With the ISSN in place, register each article with a Crossref DOI and deposit its metadata. The ISSN goes into the journal-level metadata.

6

Build discoverability

Make article pages readable by Google Scholar, publish on schedule and keep metadata complete before approaching indexing services.

JWDOI registers Crossref DOIs and deposits article metadata, giving journals a sponsored DOI prefix without joining Crossref directly. JMVRA's own articles carry DOIs under the prefix 10.56975, which is shared by the group's journals. Our Crossref DOI guide explains the direct and sponsored routes in detail.

Using the ISSN in barcodes

Print journals sold through retail channels can use the ISSN to form an EAN-13 barcode. The Indian Centre notes that it does not calculate barcode check digits, so generate the barcode with a reliable tool and test it with a scanner before printing.

Changing a Journal Title, Medium or Publisher After the ISSN

The ISSN is tied to the title and the medium. Change either and you need a new number. Other changes keep the same ISSN but must still be reported to the Centre.

Needs a new ISSN

  • The title changes (even a meaningful word change)
  • The medium changes, e.g. print becomes online

Same ISSN, but inform the Centre

  • Change of publisher
  • Change of place of publication
  • Change of frequency
  • Change of editorial policy

Changing an ISSN-assigned title without informing the National Centre will result in the ISSN being revoked. When a title does change, the guidelines ask the journal to show the old title, the old ISSN and the issues published under it on the new journal's website, so readers and databases can follow the history.

Tip: Treat the title as permanent from the first issue. A rename resets your identity in every database, so settle the name and scope during planning, not after the ISSN arrives.

How Journey & Wisdom Helps You Prepare for an ISSN

Journey & Wisdom does not issue ISSNs and cannot influence the National Centre's decision; the ISSN is free and you apply for it yourself. What the tools do is help you build the journal the Centre expects to see.

Where each tool fits in the ISSN journey
StageWhat you needRelevant tool
Before issue 1Submission portal, desk screening, reviewer invitations and reminders, revision rounds, decisionsJWJMS
Building issue 1Issue building, publication scheduling and a full record of each stepJWJMS
Quality checkSimilarity check before publication with a source-by-source reportJWSCAN
After the ISSNCrossref DOIs and metadata deposit under a sponsored prefixJWDOI
Finding servicesOne hub that lists every service in the networkJWBPN

For anything beyond these listed capabilities, such as a full journal launch package, contact the team to discuss your requirement at [email protected] or on WhatsApp at +91 91063 65667. You can also read about starting a new journal with us.

Conclusion: Getting Your ISSN the Right Way

Knowing how to get an ISSN for a journal comes down to sequence: build a credible journal, publish a complete first issue, make the website tell the truth, and then apply. In India the number is free and the process is entirely online through the ISSN National Centre at CSIR-NIScPR, but the Centre now checks editorial boards, article counts, addresses and integrity before it assigns anything. Treat those checks as a free quality review.

  • One ISSN per medium; online ISSN only after issue 1 is live
  • At least 5 articles (10 for annual titles) and at least 5 verifiable board members
  • Publisher name and Indian address shown on the site
  • Minimum 30 working days; no agents; no fee
  • Confirm the ISSN Portal record, then request the certificate and register DOIs

Authors looking for a registered, peer-reviewed home for their work can see how an ISSN is displayed in practice on JMVRA (online ISSN 2984-8911, established June 2023, monthly, multidisciplinary). Our network journals TIJER (tijer.org) and JNRID (jnrid.org) follow the same principle of one registered identifier per title.

How Journey & Wisdom Helps

JMVRA is published within the Journey & Wisdom group, which runs four shared services — similarity checking, journal management, DOI registration and conference management — and thirteen publication platforms. These are the ones that matter most for this guide. For anything not listed here, email [email protected] or message WhatsApp +91 91063 65667 to discuss your requirement.

JWJMS logo

JWJMS

Journal management system

Runs the editorial workflow: online submission portal, author dashboard, desk screening, reviewer invitations and reminders, revision rounds, decisions, issue building and publication scheduling — with a full record of every step.

jwjms.org
JWDOI logo

JWDOI

Crossref DOI registration

Registers Crossref DOIs and deposits article metadata, and gives journals a sponsored DOI prefix without joining Crossref directly — for journals, books, chapters and proceedings.

jwdoi.org
JWBPN logo

JWBPN

Network hub

Journal Wave & Book Publication Network ties the journals, book platforms and shared services together and lists every service in one place.

jwbpn.org

See every Journey & Wisdom product and platform · JW ecosystem map

How to get an ISSN for a journal in India: step by step

  1. Decide the title, medium and scope

    Fix the exact journal title, whether it is online, print or both, and a precise subject area and audience.

  2. Check for duplicate titles

    Search the Indian ISSN database on the NSL site and the ISSN Portal to make sure the title is not already in use.

  3. Build the editorial board

    Confirm at least five consenting members, senior faculty for a scholarly journal, with full affiliations and institutional emails.

  4. Publish the core website pages

    Add aims and scope, editorial board, policies, contact page and the publisher's full postal address in India.

  5. Publish a complete first issue

    Release at least 5 original, peer-reviewed articles (10 for an annual title), each with its own page and link.

  6. Check similarity and accuracy

    Screen every article for plagiarism and remove any unverifiable claims about indexing or approvals.

  7. Submit the online application

    Apply through the NSL ISSN portal for the correct medium, using the title exactly as published.

  8. Send the signed copy and enclosures

    Download the application from the status page, sign it and submit it with self-attested address proof as instructed.

  9. Track the application and answer queries

    Allow at least 30 working days and fix any issue on the live site when asked.

  10. Display the ISSN and confirm the record

    Show the ISSN with its medium on the site and PDFs, and check the record on the ISSN Portal.

  11. Request the certificate and register DOIs

    Use the certificate form once the record is confirmed, then start Crossref DOI registration for articles.

Frequently Asked Questions

How do I get an ISSN number for my journal in India?

Publish a complete first issue (online journals) or prepare a full mock-up within a month of release (print), make sure your website shows the editorial board and publisher address, then apply online through the ISSN National Centre at NSL, CSIR-NIScPR. Submit the signed application copy with address proof and track the status. The ISSN is free and processing takes at least 30 working days.

Is ISSN free in India?

Yes. The ISSN National Centre for India states that ISSNs are assigned free of charge, and that it has no agents or brokers. If someone asks you to pay for the ISSN itself, they are charging for a service you can do yourself. Some consultants charge for preparing paperwork, but payment does not change the Centre's decision or speed.

How long does it take to get an ISSN?

The Indian guidelines say the process may take a minimum of 30 working days, and longer when information or documents are missing or when many titles are involved. Add time for any query rounds. Since online journals can apply only after the first issue is released, plan for the ISSN to arrive a few months after launch.

Can I get an ISSN before publishing the first issue?

For an online journal in India, no. The Centre assigns online ISSNs only after the first issue is released with enough articles. For a print journal, you may request an ISSN up to one month before the first issue with full information and an advanced mock-up, but the record is formally registered only after proof of publication is received.

How many articles are needed to get an ISSN?

For non-annual online journals, the guidelines treat at least 5 articles as the minimum for a complete issue; for annual publications the minimum is 10. For print, the first issue should include the title page, editorial page and at least 5–6 original articles. A first issue below these numbers leads to a deferred assignment.

What is the difference between print ISSN and e-ISSN?

They are separate numbers for separate media. The print ISSN identifies the printed version and the e-ISSN (online ISSN) identifies the online version of the same title. Each must be displayed only on its own medium. The ISSN-L, a linking ISSN shown in the ISSN Portal record, groups the two versions together.

What documents are required for ISSN registration?

The Indian guidelines list the signed copy of the online application, self-attested address proof of the publisher (Aadhaar, Voter ID, driving licence or passport), and for print the first issue or cover, title, editorial page and 5–6 articles. For online titles you give the journal URL, plus a temporary login if access is by subscription.

Does an ISSN mean my journal is approved or indexed?

No. An ISSN only identifies a serial title. The Indian Centre states that assigning an ISSN does not amount to approving a journal or its contents, and publishers should not describe their journals as approved by NSL or NIScPR. Indexing in databases is a separate process with its own criteria and no guarantee.

Do I need RNI registration to get an ISSN for an academic journal?

For journals of a scientific, technical and academic nature, no. The current Indian ISSN guidelines say such journals do not fall under the registration requirement of the Press and Registration of Periodicals Act, 2023, so RNI registration is not mandatory for a print ISSN. News publications and general periodicals are a different case.

Can an individual apply for an ISSN?

Yes, an individual publisher can apply, provided the publication is a genuine serial and meets all conditions: a complete first issue, at least five qualified editorial board members, a website with the publisher's full Indian address and policies. Many journals are run by institutions or societies, and those should be linked from the institution's own website.

Do I need a new ISSN if I change my journal's name?

Yes. A title change or a medium change requires a new ISSN. Changing an ISSN-assigned title without informing the National Centre leads to the ISSN being revoked. Changes of publisher, place, frequency or editorial policy keep the same ISSN, but you should inform the Centre about them.

Why was my ISSN application rejected?

Common reasons include applying before the first issue, too few articles, fewer than five board members or board members without full affiliation, unverifiable indexing claims, a missing Indian publisher address, plagiarised content and a title that differs between the form and the site. After a rejection, you must submit a fresh application with all documents.

How do I check my ISSN application status?

Use the Application Status page on the NSL ISSN portal, where you can also download your filled application form. Once an ISSN is assigned, check that the record has been confirmed on the ISSN Portal (portal.issn.org), because the Indian Centre issues the registration certificate only after that confirmation.

Can I use one ISSN for both the print and online versions?

No. The Indian guidelines say an ISSN assigned to one format must not be used for another format. Apply separately for print and online, and print each number only on its own medium. Using the online number on paper copies is a common error that databases flag as a metadata conflict.

What should I do after getting an ISSN?

Display it with its medium on the site and every PDF, confirm the ISSN Portal record, request the certificate, send any validation copies the Centre needs, keep publishing on schedule, and register Crossref DOIs for your articles. A sponsored DOI service such as JWDOI can deposit article metadata without direct Crossref membership.

Publish Your Research in JMVRA

Peer-reviewed, open access (CC BY 4.0), monthly and multidisciplinary · ISSN 2984-8911 · ₹971 for Indian authors and US$41 for international authors, payable only after acceptance.

Just ₹971 INR
Publish in a UGC-aligned peer-reviewed journal · ₹971 INR Indian authors · $41 USD international · Impact Factor 11.25
Submit Paper