About HoursCalc
Free calculators for the hours on a time card: built for hourly workers checking a paycheck and the people who run payroll.
How the maths works
- Clock times become minutes after midnight. An end earlier than the start means the shift crossed midnight, so 24 hours are added.
- Minutes are kept exact until the result; decimal hours are minutes ÷ 60, rounded to two places for display.
- Daylight saving uses the IANA time zone rules built into your browser.
- Overtime applies daily rules first, then weekly rules to the remaining regular hours, so no hour counts twice. Each workweek is separate.
The time maths is covered by automated tests for overnight shifts, breaks, rounding, decimal conversion, DST and overtime splits.
Sources
- U.S. Department of Labor, Wage and Hour Division: Fact Sheet #23 (overtime), Fact Sheet #22 (hours worked), Fact Sheet #56A (regular rate), Fact Sheet #17A (exemptions).
- 29 CFR Part 785: hours worked, including §785.18 (rest), §785.19 (meal periods) and §785.48 (rounding).
- California Labor Code §510 and DLSE Overtime FAQ; Alaska AS 23.10.060; Nevada NRS 608.018; Colorado COMPS Order.
Not legal or payroll advice
Everything here is general information to help you check your numbers. Laws have exceptions and change; for a dispute or a payroll decision, contact your state labour department, the Wage and Hour Division, or a qualified adviser.