NIH Grants: R01, R03, or R21?

What is the difference between an R01, an R03 and an R21?


The R01 Research Project Grant Program is the original and historically oldest grant mechanism used by NIH.

The Research Project (R01) grant is an award made to support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing the investigator’s specific interest and competencies, based on the mission of the NIH.

A typical R01 has:

  • Duration: Up to 5 years
  • Budget limitation: None, but requires pre-approval if over $500,000 direct costs

The R03 Small Research Grant Program will support small research projects that can be carried out in a short period of time with limited resources.

The common characteristic of the small grant is the provision of limited funding for a short period of time. Examples of the types of projects that ICs support with the R03 include the following:

  • Pilot or feasibility studies
  • Secondary analysis of existing data
  • Small, self-contained research projects
  • Development of research methodology
  • Development of new research technology

A typical R03 has:

  • Duration: 2 years
  • Budget limitation: $100,000 direct costs

The R21 Exploratory/Developmental Research Grant Program is intended to encourage exploratory/developmental research by providing support for the early and conceptual stages of project development.

  • Exploratory, novel studies that break new ground or extend previous discoveries toward new directions or applications.
  • High risk high reward studies that may lead to a breakthrough in a particular area, or result in novel techniques, agents, methodologies, models or applications that will impact biomedical, behavioral, or clinical research.
  • Projects should be distinct from those supported through the traditional R01 mechanism.

A typical R21 has:

  • Duration: 2 years
  • Budget limitation: $275,000 direct costs (no more than $200,000 direct costs per year)
  • Preliminary data not required
  • Not renewable
This entry was posted in NIH and tagged . Bookmark the permalink.