DIY Cost Tools
Shift Length Calculator
Calculate gross and paid shift length from start time, end time, and an unpaid break, including overnight shifts.
How to use this calculator
- Replace the example values with your own measurements or planning assumptions.
- Keep every value in the unit printed beside its field.
- Select Calculate and review the result together with the formula and limitations below.
Formula and method
Gross minutes equal end time minus start time, adding 24 hours when the shift crosses midnight. Paid time subtracts the unpaid break.
Results are hidden whenever an input changes or validation fails, so an old answer cannot be mistaken for a current calculation.
Worked example
Shift start = 22:00; Shift end = 06:30; Unpaid break = 30 minutes. The calculator returns Gross shift = 8.5 hours; Paid time = 8 hours; Paid time formatted = 8 h 0 min; Break share = 5.88%.
The worked example uses the same default values displayed in the calculator.
Limitations and safety
Frequently asked questions
Does the calculator handle an overnight shift?
Yes. When the end time is not later than the start time, the calculator treats the end as occurring the next day.
Why might the real result differ?
This tool does not apply labor-law rules, paid-break policies, rounding policies, overtime thresholds, or daylight-saving clock changes.
How should I round the answer?
Keep extra precision while planning, then round up when purchasing whole containers, bags, pieces, or stock lengths. Follow the output labels and supplier packaging.
Review notes and reference
Reviewed October 4, 2026. The formula was checked against the displayed worked example, and the script was tested for defaults, boundaries, invalid formats, condition-specific errors, and recovery. Reference: NIST Time and Frequency Division. Explanations and examples are original.