NIH Activity Codes: Complete List of R, K, F, T, P, U Grant Types
A full reference for every major NIH activity code. Funding amounts, eligibility, and use case for each grant type — from R01 and R21 to K99/R00, F31, F32, T32, P01, U01, and the NIH Director's high-risk awards.
NIH activity codes are 3-character identifiers (R01, K99, F32, T32, P01, U01, etc.) that classify NIH grants by funding mechanism. The code tells you who can apply, what the grant supports, the typical budget cap, and the project duration. The first letter groups codes into series.
R01
Research Project Grant
R21
Exploratory Grant
K99/R00
Pathway to Independence
F32
Postdoc Fellowship
Series at a glance
- R R Series — Investigator-led research grants (R01, R03, R21, R35, etc.)
- K K Series — Career development awards (mentored or mid-career)
- F F Series — Individual fellowships (predoc and postdoc)
- T T Series — Institutional training grants (institution recruits trainees)
- P P Series — Program project and center grants (multi-PI, shared theme)
- U U Series — Cooperative agreements (NIH staff substantial involvement)
- D DP Series — NIH Director's awards for high-risk research
RR Series — Research Grants
| Code | Name | Purpose | Funding | Duration | Eligibility |
|---|---|---|---|---|---|
| R01 | Research Project Grant | Discrete, specified research project led by a PI | No fixed cap; most $250K–$500K direct/yr | 3–5 years (renewable) | Any qualified investigator with preliminary data |
| R03 | Small Research Grant | Small, short-term projects (pilot studies, secondary analyses) | Up to $50K direct/yr | Up to 2 years | Any qualified investigator |
| R15 | AREA / REAP Award | Strengthen research at undergraduate-focused institutions | Up to $300K direct over project | Up to 3 years | Faculty at eligible non-research-intensive institutions |
| R21 | Exploratory/Developmental Grant | Novel, high-risk/high-reward exploratory research | Up to $275K direct over 2 years | Up to 2 years | Any qualified investigator; preliminary data not required |
| R34 | Planning Grant | Planning for clinical trials or large-scale studies | Up to $450K direct over project | Up to 3 years | Investigators planning trials |
| R35 | Outstanding Investigator Award | Long, flexible support for productive investigators (one program per lab) | Varies by IC ($600K–$1.5M direct/yr) | 5–8 years | Established investigators with strong track record |
| R37 | MERIT Award | R01 with extended funding for top-scoring established investigators | Same as R01 | Up to 7 years | By IC selection from top R01 applicants |
| R41/R42 | STTR (Phase I / II) | Small Business Technology Transfer with academic partner | Phase I: ~$300K; Phase II: ~$2M | I: 1 yr · II: 2 yrs | Small businesses with academic collaborator |
| R43/R44 | SBIR (Phase I / II) | Small Business Innovation Research | Phase I: ~$300K; Phase II: ~$2M | I: 1 yr · II: 2 yrs | For-profit small businesses |
KK Series — Career Development Awards
| Code | Name | Purpose | Funding | Duration | Eligibility |
|---|---|---|---|---|---|
| K01 | Mentored Research Scientist Career Dev. Award | Career development for new investigators needing mentored training | Salary up to ~$100K + research support | 3–5 years | PhDs in early career; varies by IC |
| K08 | Mentored Clinical Scientist Career Dev. Award | Mentored research training for clinician-scientists doing lab/translational research | Salary + ~$30K research/yr | 3–5 years | Clinicians (MD, DO, DDS, etc.) within ~5 yrs of training |
| K23 | Mentored Patient-Oriented Research Career Dev. | Mentored training for clinicians doing patient-oriented research | Salary + ~$30K research/yr | 3–5 years | Clinicians focused on patient-oriented research |
| K99/R00 | Pathway to Independence Award | Postdoc → faculty transition (mentored K99 → independent R00) | K99: ~$90K–$130K/yr · R00: ~$249K/yr | K99: 1–2 yrs · R00: up to 3 yrs | Postdocs typically within 4 yrs of PhD |
| K24 | Mid-Career Investigator Award in Patient-Oriented Research | Protected time for established clinician-scientists to mentor | Salary + research support | 3–5 years | Mid-career clinicians with active patient-oriented research |
| K25 | Mentored Quantitative Research Career Dev. | Brings quantitative scientists (engineers, physicists) into biomedical research | Salary + research support | 3–5 years | Quantitative scientists transitioning to biomedical research |
| K43 | International Research Career Dev. Award | Career development for scientists in low/middle-income countries | Varies by country | 3–5 years | Researchers in eligible low/middle-income countries |
FF Series — Individual Fellowships
| Code | Name | Purpose | Funding | Duration | Eligibility |
|---|---|---|---|---|---|
| F30 | Individual Predoctoral MD/PhD Fellowship | Combined MD/PhD or other dual-degree predoctoral training | Stipend + tuition + research allowance | Up to 6 years | Students in dual-degree programs (MD/PhD, DO/PhD, etc.) |
| F31 | Individual Predoctoral Fellowship | PhD predoctoral research training | Stipend + tuition + research allowance | Up to 5 years | PhD students in biomedical research |
| F32 | Individual Postdoctoral Fellowship | Postdoctoral mentored research training | NRSA stipend + research allowance | Up to 3 years | Recent PhDs (within ~5 yrs) |
| F33 | Senior Fellowship | Mid-career retraining for established investigators | Stipend + research allowance | Up to 2 years | Established investigators changing fields |
| F99/K00 | Predoc-to-Postdoc Transition Award | Transition from PhD candidacy through early postdoc | Stipend + research allowance | F99: ~2 yrs · K00: up to 4 yrs | Late-stage PhD students (cancer-focused; NCI program) |
TT Series — Institutional Training Grants
| Code | Name | Purpose | Funding | Duration | Eligibility |
|---|---|---|---|---|---|
| T32 | Institutional Research Training Grant | Institution-administered predoc/postdoc training program | Stipends + tuition for trainees | 5 years (renewable) | Awarded to institutions; trainees apply through program |
| T35 | Short-Term Institutional Training | Short-term research experiences (8–12 weeks) for health-professional students | Short-term stipends | 5 years | Awarded to institutions |
| T90/R90 | Interdisciplinary Training | Predoc/postdoc training in interdisciplinary areas | Stipends | 5 years | Awarded to institutions |
PP Series — Program & Center Grants
| Code | Name | Purpose | Funding | Duration | Eligibility |
|---|---|---|---|---|---|
| P01 | Program Project Grant | Multi-project, multi-PI program with shared theme and cores | Multi-million/yr (varies by IC) | 5 years | Established investigator teams with shared scientific theme |
| P30 | Center Core Grant | Shared resource cores supporting NIH-funded investigators | Varies | 5 years | Institutions with critical mass of related research |
| P50 | Specialized Center Grant | Topic-specific multi-component research center (e.g., SPORE) | Multi-million/yr | 5 years | Established research teams |
UU Series — Cooperative Agreements
| Code | Name | Purpose | Funding | Duration | Eligibility |
|---|---|---|---|---|---|
| U01 | Research Project — Cooperative Agreement | Investigator-led research with NIH staff substantial involvement | R01-like; varies | 3–5 years | Investigators on NIH-led initiatives |
| U54 | Specialized Center — Cooperative Agreement | Multi-component centers with NIH program involvement | Multi-million/yr | 5 years | Multi-PI/multi-institution teams |
| UM1 | Multi-Component Cooperative Agreement | Large multi-component research with NIH involvement | Multi-million/yr | 5 years | Multi-component team programs |
DD / DP Series — NIH Director’s High-Risk Research
| Code | Name | Purpose | Funding | Duration | Eligibility |
|---|---|---|---|---|---|
| DP1 | NIH Director's Pioneer Award | High-risk/high-reward research from exceptional individual scientists | $700K direct/yr | 5 years | Highly innovative individual scientists |
| DP2 | NIH Director's New Innovator Award | Bold, untested ideas from early-stage investigators | $1.5M direct over project | 5 years | Early-stage investigators within ~10 yrs of terminal degree |
| DP5 | NIH Director's Early Independence Award | Skip the postdoc — direct PhD-to-PI transition | $250K direct/yr | 5 years | Recent PhDs (within ~1 yr) skipping postdoc training |
How to choose the right NIH grant
- 1. Career stage — Match the grant to where you are: F31 for PhD students, F32 for postdocs, K99/R00 for the postdoc-to-faculty transition, R01 for established faculty.
- 2. Project maturity — Strong preliminary data → R01. New, untested idea → R21 or R03. Bold high-risk concept → DP1 / DP2.
- 3. Clinician vs. PhD — Clinicians doing lab research → K08. Clinicians doing patient-oriented research → K23. PhD scientists → K01 or K25.
- 4. Solo vs. team — Single-PI work → R01 or R21. Multi-PI center with shared cores → P01, P50, U54.
- 5. Trainee vs. institutional — You apply yourself for individual fellowships (F series) or career development (K series). Institutional T32 trainees apply through the host program at their institution.
Frequently asked questions
What is an NIH activity code?
An NIH activity code is a 3-character identifier (like R01, K99, F32, T32) that tells you the funding mechanism: who can apply, what the grant supports, how big the budget can be, and how long the project lasts. The first letter groups codes into series (R = research grants, K = career development, F = individual fellowships, T = institutional training, P = program/center, U = cooperative agreement, DP = NIH Director’s awards).
What is the difference between R01 and R21?
R01 is the standard NIH research grant: 3–5 years, larger budget (typically $250K–$500K direct per year), and usually requires preliminary data. R21 is exploratory: up to 2 years, smaller budget ($275K direct over the entire grant), and explicitly does NOT require preliminary data. R21 is for testing a new idea; R01 is for executing an established research program.
What is the difference between K99/R00 and other K awards?
K99/R00 is a two-phase transition award: K99 supports 1–2 years of mentored postdoc work, and R00 provides 3 years of independent funding once you accept a faculty job. Other K awards (K01, K08, K23, K24) support career development at a single phase — usually mentored research time for early-career scientists or clinicians.
What is the difference between F31 and F32?
F31 is an individual predoctoral fellowship for PhD students. F32 is an individual postdoctoral fellowship for recent PhDs. Both pay an NRSA stipend plus tuition/research allowance, but they target different career stages.
What is the difference between T32 and F32?
T32 is awarded to an institution that runs a training program; trainees apply through the program. F32 is awarded directly to an individual postdoc. T32 funds the program; F32 funds you.
What is the difference between R01 and U01?
Both fund similar-sized research projects. The difference is involvement: U01 is a cooperative agreement, meaning NIH program staff are substantively involved in the project (steering committees, milestones, NIH-driven decisions). R01 is an investigator-led grant with minimal NIH involvement once funded.
How do I look up grants by activity code?
Use the PI Finder or Trends search and apply the activity code filter (R01, K99, F32, etc.). You can also search NIH RePORTER directly. Both methods will return all funded projects with that activity code, plus the PIs, institutions, and project details.
Which NIH grant should I apply for?
Pick by career stage and project maturity. Predoctoral students: F31 (or F30 for MD/PhD), T32 if your institution has one. Postdocs: F32, K99/R00 (if planning faculty transition). New PIs: R21 (no preliminary data) or R03 (small project), then R01. Established PIs: R01, R35 (one-program-per-lab), or P/U series for large multi-component work. Clinicians: K08 (lab research) or K23 (patient-oriented research).
What is the average size of an NIH R01?
Most R01 awards are $250,000 to $500,000 in direct costs per year, for 3–5 years. Direct costs exclude institutional indirect costs (overhead), which typically add another 50–70%. The exact cap depends on the institute and the specific funding announcement.
Live NIH funding data by activity code
Each major activity code has its own page with live recently awarded grants, top funded institutes, and per-mechanism stats from NIH RePORTER. Pick a code:
