NSF Summer Salary Calculator and the Two-Month Rule
Estimates for planning. Your institution's rates, policies, and the sponsor's terms govern.
The NSF two-month rule
NSF limits the salary requested for each senior/key person to no more than two months of their regular salary in any one year. The limit counts salary from all NSF-funded grants together, not each award separately.
More than two months is allowed when it is disclosed in the proposal budget, justified in the budget justification, and specifically approved by NSF in the award notice. Many institutions define the year as their fiscal year, so check your local policy.
How the calculation works
- Monthly rate = academic-year salary ÷ 9 for 9-month appointments, or annual salary ÷ 12 for 12-month appointments.
- Salary requested = monthly rate × months requested.
- Fringe = salary requested × your institution's applicable fringe rate.
- NSF months this year = months on this proposal + months already funded on other active NSF awards.
Worked example
| Item | 9-month faculty | 12-month researcher |
|---|---|---|
| Base salary | $126,000 | $126,000 |
| Monthly rate | $14,000 | $10,500 |
| 1.5 months requested | $21,000 | $15,750 |
| Fringe at 25% | $5,250 | $3,938 |
| Salary + fringe | $26,250 | $19,688 |
Adding 0.5 months already funded on another NSF award brings the total to 2.0 months, right at the limit.
Mistakes to avoid
- Dividing a 9-month salary by 12. That understates the summer monthly rate by a quarter.
- Checking the two-month limit one award at a time. It applies across all NSF awards in the year.
- Requesting more than two months without saying so in the budget justification.
Frequently asked questions
How is summer salary calculated?
Divide the 9-month academic-year salary by 9 to get the monthly rate, then multiply by the summer months requested. A $126,000 salary gives a $14,000 monthly rate, so two summer months is $28,000.
What is the NSF two-month rule?
NSF limits salary for each senior/key person to two months of regular salary per year, counted across all NSF awards. More is allowed only if disclosed, justified, and approved by NSF.
Does the two-month rule apply to academic-year salary?
Yes. It covers salary from NSF grants paid at any time in the year, including academic-year buyout, not only summer salary.
Does the rule apply to postdocs and graduate students?
No. It applies to senior/key personnel, such as the PI, co-PIs, and other faculty-level senior personnel.
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