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Eight hours of GS night pay at $33.84
The hourly rate is 33.84, the GS-9, step 1, rate on the OPM sheet. The differential is 10 percent, the General Schedule night-pay rate in 5 CFR 550.121. The hours box is 8. Those 8 hours are one tour. Replace them with the hours that actually earn the differential.
Hourly rate: 25% lower
Change hourly rate to 25.38 while keeping the other example values the same.
Hourly rate: 25% higher
Change hourly rate to 42.3 while keeping the other example values the same.
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Quick answer
What does the Shift differential pay calculate?
What does a percent shift differential add to base pay? This calculator uses hourly rate, differential, and hours on the differential to estimate a percent of the hourly rate, on the hours that earn it immediately in your browser.
With the values currently entered, the result is $27.04 — added for the hours you typed. It also shows premium per hour, base pay for these hours, and pay for these hours.
How to use the Shift differential pay
- Replace the example values with your own numbers.
- Review the result and supporting figures as they update automatically.
- Check the formula and assumptions before using the estimate for a decision.
Inputs used
- Hourly rate
- Differential — entered in %
- Hours on the differential — entered in hours
Shift differential pay formula
Premium per hour = hourly rate × differential percent, rounded to the nearest cent. Differential pay = that premium × hours.
Assumptions
- The OPM fact sheet "How to Compute Rates of Pay," using Salary Table 2026-DCB, takes GS-9, step 1, at $70,623. Divided by 2,087 hours under 5 U.S.C. 5504, the hourly rate is $33.84. Night pay is 10 percent of that rate under 5 CFR 550.121, which the sheet prints as $3.38. Rates round to the nearest cent, and half a cent and over rounds up.
- The hours box is the hours that earn the percent. For General Schedule night pay, that is regularly scheduled work between 6 p.m. and 6 a.m. 29 CFR 778.207(b) includes a nightshift differential in the FLSA regular rate, whether it is a percent of the base rate or extra cents per hour. Overtime on that regular rate is a separate calculation. A private policy uses the percent in the agreement. The 10 percent here is the GS example.
Verify the inputs
Authoritative sources
These sources explain the definitions, factors, or rules behind this tool. Their geographic scope is shown because an official source for one country is not automatically valid somewhere else.
GS-9, step 1, is $70,623. Divided by 2,087 hours, the hourly rate is $33.84. Night pay is 10 percent of that rate under 5 CFR 550.121, printed as $3.38. Rates round to the nearest cent, and half a cent and over rounds up.
Other types of contract premium pay distinguishedUS Department of Labor — 29 CFR 778.207Scope: US Fair Labor Standards Act regular rateRequires nightshift differentials in the regular rate, whether they are a percent of the base rate or an addition of so many cents per hour. They are not overtime premiums.
Night shift differential for Federal Wage System employeesUS Office of Personnel ManagementScope: US Federal Wage System night differentialPays 7.5 percent when most of a regularly scheduled nonovertime shift falls between 3 p.m. and midnight, and 10 percent when most falls between 11 p.m. and 8 a.m. The differential covers the entire shift.
Sources do not endorse Calculum. Check the source date, scope, and your own documents before making a financial, tax, insurance, or reporting decision.
Practical guide
Shift differential pay example and edge cases
A percent shift differential is the hourly rate times the percent, times the hours that earn it. The OPM pay fact sheet takes a 2026 GS-9, step 1, at $70,623 on Salary Table 2026-DCB. Divided by 2,087, the hourly rate is $33.84. Night pay is 10 percent of that rate, printed as $3.38.
Example: Eight hours of GS night pay at $33.84
The hourly rate is 33.84, the GS-9, step 1, rate on the OPM sheet. The differential is 10 percent, the General Schedule night-pay rate in 5 CFR 550.121. The hours box is 8. Those 8 hours are one tour. Replace them with the hours that actually earn the differential.
- Hourly rate
- 33.84
- Differential
- 10 %
- Hours on the differential
- 8 hours
Calculated result$27.04added for the hours you typed
The premium is 3.38 an hour, the figure the sheet prints after rounding to the cent. Over 8 hours the differential is 27.04. Base pay for those hours is 270.72, and the two together are 297.76.
Example results use the default display profile. The calculator above follows your selected country and units.
How to read the result
- Read the 27.04 first. It is 3.38 times 8. The 3.38 is 33.84 times 10 percent, rounded to the nearest cent. The sheet counts half a cent and over as the next cent. 33.84 times 0.10 is 3.384, which rounds to 3.38.
- 29 CFR 778.207(b) puts a nightshift differential into the regular rate before FLSA overtime, whether the premium is a percent of the base rate or extra cents per hour. The 297.76 is straight time for these 8 hours, before any overtime premium on that regular rate.
Edge cases worth checking
The policy pays cents per hour
The same regulation allows an addition of so many cents per hour. DOL Fact Sheet 54 shows a personal care assistant at 8 an hour with a 1 dollar evening differential. One dollar on an 8 dollar rate is 12.5 percent. Type 12.5. A 1 in the percent box is 1 percent of the rate, which on 33.84 is 0.34 an hour.
The whole shift is not night work
General Schedule night pay follows hours worked between 6 p.m. and 6 a.m. Federal Wage System night differential is different. OPM pays 7.5 percent for a whole shift when most scheduled hours fall between 3 p.m. and midnight, and 10 percent when most fall between 11 p.m. and 8 a.m. Type the hours the rule you are using pays, and the percent that rule names.
What changes the result most
Hourly rate
Test a lower and higher hourly rate. A small percentage change can move the final result more than expected.
Differential
Test a lower and higher differential. A small percentage change can move the final result more than expected.
Hours on the differential
Keep hours on the differential on the same time basis as the other inputs. Monthly and annual values are easy to mix up.
Try a different scenario
Small changes show whether the answer is stable or sensitive.
Hourly rate: 25% lower
25.38$20.32added for the hours you typed
Hourly rate: 25% higher
42.3$33.84added for the hours you typed
Differential: 25% higher
13 %$35.20added for the hours you typed
Common mistakes
Check hourly rate
The OPM fact sheet "How to Compute Rates of Pay," using Salary Table 2026-DCB, takes GS-9, step 1, at $70,623. Divided by 2,087 hours under 5 U.S.C. 5504, the hourly rate is $33.84. Night pay is 10 percent of that rate under 5 CFR 550.121, which the sheet prints as $3.38. Rates round to the nearest cent, and half a cent and over rounds up. Make sure this matches the number you enter.
Keep hours on the differential consistent
The hours box is the hours that earn the percent. For General Schedule night pay, that is regularly scheduled work between 6 p.m. and 6 a.m. 29 CFR 778.207(b) includes a nightshift differential in the FLSA regular rate, whether it is a percent of the base rate or extra cents per hour. Overtime on that regular rate is a separate calculation. A private policy uses the percent in the agreement. The 10 percent here is the GS example. Use the same units and time period throughout the calculation.
Do not rely on one shift differential pay scenario
Run a cautious case and an optimistic case. The range is often more useful than one exact-looking number.
Use this result well
What does a percent shift differential add to base pay?
It does not replace a quote, contract, accountant, or local employment guidance.