NIH Grant Numbers Demystified

I’ve been asked this a lot lately, so without further ado …

Application type – Activity code – Institute – Serial no. – Suffix (Year – Amendment -Supplement)
1 R01 AI 83723 01 A1 S1

Number on a grant application identifying application type (e.g., new is type 1), activity code (e.g., research project grant is R01 ), organization to which it is assigned (e.g., NIAID is AI), serial number assigned by the Center for Scientific Review, suffix year showing the support year (budget period) for a grant, amendment (if resubmitted), and other information, e.g., administrative supplement, fellowship institutional allowance. For contracts, the suffix is replaced by a modification number.

Application type is the first digit on an application identification number:

Type 1 — New — provides PHS support for a new research project grant.

Type 2 — Renewal — extends a project period that would otherwise expire for one or more grant budget periods; applications are peer reviewed and compete for funding.

Type 3 — Supplement, a.k.a. administrative supplement — adds funds to a grant without peer review.

Type 4 — Extension — provides time and funds beyond recommended levels. Applies only to MERIT and Small Business Innovation Research Fast Track applications.

Type 5 — Noncompeting continuation — continues support in the out years of a grant; does not compete for funds.

Type 6 — Change of grantee — transfers a grant when one organization buys out another, also called successor of interest.

Type 7 — Change of grantee — transfers a grant from one institution to another.

Type 8 — Change of NIH institute — transfers a grant from one institute to another.

Type 9 — Change of institute — continues support for grant transferred from one institute to another.

Activity code is the 3-digit identifier of an award type, e.g., R01 is a research project grant. Activity codes are grouped together to form funding mechanisms. The major mechanism series are:

F — fellowships
K — career development awards
N — research contracts
P — program project and research center grants
R — research project grants
S — research-related programs (equipment etc.)
T — training grants
U — cooperative agreements
Y — interagency agreements

More info on the major funding mechanisms can be found on the Web and in a massive PDF file on activity codes & definitions.

The two-letter code indicates the primary funding institute (more & more awards will be shared, but only the primary IC is incorporated in the grant application number). Most are relately obvious (HL=NHLBI, DK=NIDDK), but others are less so (HS=AHRQ, TW=FIC), but you can check the NIH abbreviation glossary for clarification.

The serial number is assigned by the Center for Scientific Review (CSR).

The suffix starts with and often only includes the current funding year (-01 for first year etc.). In years in which an amended application (resubmission) is funded, an A1 will be appended to the year if the application was funded on its first amendment or A2 if the application was funded on its second & final amendment/resubmission. Applications for diversity or administrative supplements are identified by incorporation of an “S”, with the number referring to whether this is the first, second, etc. supplement requested for the parent grant (which has its own separate number *without* the “S” in the suffix.



  1. This is immensely helpful. Thank you very much for posting this information for the scientific admin geeks out there.

    Very glad to help! Favorite part of my job. Please feel free to ask questions if there are other mysteries I might be able to clear up. – writedit

  2. richard said

    i work for uic. i am a grant specialist. i am working on an nih grant. i have not seen a grant number look like this 3 RO1 AG016303-09W1 i understand the 09 is the ninth year, but what does the W1 mean? Please help

  3. It appears that the W# suffix is used to indicate ARRA-funded supplements to non-ARRA-funded parent grants.

    • Paula Roth said

      Actually, the W recognizes where the application is in the review process. Being baffled by this issue myself, I contacted NIH and was advised W is reassigned as S once the grant is ready to be released by the grants specialists.

      • writedit said

        Cool. Thanks much for sharing the results of your taking the initiative to track down the meaning of the mysterious W. – writedit

      • hohum said

        I also just had a grant number with W show up yesterday. The thing is, I received an email indicating my ARRA supplement would NOT be funded at the beginning of the month. Why is this showing up just now on Commons?

      • writedit said

        Perhaps a change of funding priorities after the RC1s were cleared off the IC’s plate? I’d suggest you contact your PO to confirm what’s going on.

      • hohum said

        I haven’t been getting any info from my PO. Does the fact I have this W mean that my supplement will be funded? Or do unfunded or failed supplements also have this designation on eRA commons?

  4. amaryllis said

    The W1 has been attached to my supplement and it’s being analysed. In the “status” section it has changed to “to be paid”. I assume a good sign.

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