National Science Foundation (NSF) has two-month salary cap known as the two-ninths-rule:

``Summer salary for faculty members on academic-year appointments is limited to no more than two-ninths of their regular academic-year salary. This limit includes summer salary received from all NSF-funded grants.''

What would happen if an individual has already reached the maximum limit of two months of summer salary from NSF and a new proposal is being recommended for funding? While the distinction between "current and pending" support should make this situation clear, is it necessary for the principal investigator (PI) to communicate this separately with the program officer? Moreover, could this potentially result in the rejection of the new proposal?

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    Some guidance but I don’t have experience in how this works myself. finance.uw.edu/pafc/nsf-2month-rule
    – Dawn
    Commented Jun 22, 2023 at 1:50
  • @Dawn Yes, this is usefule! It has "a grantee can internally approve an increase or decrease in person months devoted to the project after an award is made, even if doing so results in salary support for senior personnel exceeding the two-month salary policy. "
    – Bob
    Commented Jun 22, 2023 at 2:26
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    Well I think it says you need NSF approval unless the overage is a result of budget changes.
    – Dawn
    Commented Jun 22, 2023 at 4:29
  • I checked this with others and it seemes we can decrease effort by 25% in any one year without requiring approval.
    – Bob
    Commented Jun 22, 2023 at 21:20
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    That's correct. This should be done in existing projects too. Meaning that if you have 1+1+0.5 (for example) you could reduce the first two 25% to make the total salary 0.75+ 0.75+ 0.5 = 2.
    – Bob
    Commented Jun 23, 2023 at 0:27

2 Answers 2


Research admin here. Essentially, this rule is very fuzzy and interpreted differently by different folks. Some schools are strict, others generous. NSF wrote a clarification in 2017 that clarified nothing. I tend to find in CISE that the Program Officer (PO) makes you promise not to charge more than 2 months prior to taking the new award. At some institutions, this means you have to cost share the effort to track an effort commitment. If it is less than a 25% reduction from the commitment, there is no requirement for prior approval. Thus we usually cut 24% across each fund to get the time back. Personally, I do not charge more than 2 if the effort was committed up front. I only let folks charge more in a true rebudget situation.

Being over-committed generally doesn't result in the proposal being turned down unless it's really bad (usually total commitments). Still, they will ask you about the commitment. It's not a cold rejection email. This process is called a "just in time" or JIT. When you get the request, you should forward it to your assigned research administrator for assistance.

  • Thank you. Let's say you are overcommitted but you do not want to charge more than two months. What happens to the remaining fund? What happens to next proposals in terms of PI salary? Can one ask zero money for themselves?
    – Bob
    Commented Jul 23, 2023 at 12:39
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    @Bob, yes, some faculty will request 0 effort on the budget, and you can put a statement in the Facilities page that you are not making a large quantifiable commitment of time, but will be giving effort as needed. A research administrator should be able to help with the phrasing to avoid the implications of committing voluntary cost share. If you are not in the budget, you have to delete your name from the budget pages in Research.gov. On the Current and Pending file, you have to give your voluntary effort even though $0 will be charged. NSF is pretty good about rebudgets to spend on the lab. Commented Jul 23, 2023 at 18:23
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    If you are overcommitted (truly), you can put in a formal request through Research.gov to lower your effort, but you need a justification. E.g., if you are a junior PI who was able to hire a fantastic postdoc, maybe you go from 1 month to 0.50, and use that funding on the postdoc instead. This is a routine sort of adjustment -- just make sure your request makes sense. You don't want to have the PO come back and say "you really think a second year grad student can replace your expertise on X?" The main thing is you need to make sure you do not create a change in scope. Commented Jul 23, 2023 at 18:27

First of all, "recommended for funding" is not funded yet.

Part of the (long, multi-party) process following the recommendation involves a bunch of checks by NSF "career" people (i.e., not academics in rotation at NSF), which includes compliance with all the regulations. This does not answer your question, but it's an important distinction.

Since your proposal is recommended for funding, you should be able to see the panel reviews in research.gov, and also who the program manager who administered the panel was (in case you already don't know). I would suggest getting in touch with them, and ask.


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