Shift Length Calculator

How to use this calculator

Enter Start (24h decimal), End (24h decimal), Unpaid break (minutes). The result updates in your browser as you edit an input. The prefilled values are examples only.

How the estimate works

Subtract start from end, allowing for a shift across midnight, then subtract the unpaid break. Enter 17.5 for 5:30 p.m.

What can change the answer?

Breaks and overnight shifts are easy to misrecord. This decimal-hour input does not accept 5:30 as a time notation: enter 17.5 for 5:30 p.m. A shift exactly 24 hours long needs separate handling.

Before relying on the result

Check that the figures use the same units and period. Compare the result against a current label, quote, contract, employer policy, or official dataset when appropriate. This estimate does not include factors you have not entered.

Further reference

For source data or a more detailed method, see U.S. Department of Labor: overtime fact sheet. The calculator does not automatically import data from this source.

Worked example with the default inputs

A shift from 22 to 6 crosses midnight and lasts eight elapsed hours. With a 30-minute unpaid break it becomes 7.5 hours. Keep the shift dates in the underlying work record.

Interpret the result in a planning record

The shift length calculator allows an end time earlier on the clock than the start time, treating it as the following day. This helps with a 10 p.m. to 6 a.m. shift. It represents a single shift shorter than 24 hours, so a full-day or multi-day record needs a separate approach rather than an identical start and end time.

Save the input values, units and result together. Change one uncertain input at a time so you can see which assumption moves the answer. A displayed decimal is arithmetic precision, rather than evidence that the measurements or rates are equally precise.

More tools

Read the How to Check a Time Card and Overtime Estimate guide →