Methodology and sources
How Clockfigure calculators work, and where their numbers come from.
How the calculators are built
Each calculator runs entirely in your browser; nothing you type is sent anywhere. Results are rounded only for display, and every page shows the formula it uses and a worked example you can check by hand.
Time, pay and date rules
Time is added in base 60 (60 seconds to a minute, 60 minutes to an hour). Shifts that end earlier than they start are treated as crossing midnight. Decimal hours are minutes divided by 60.
Overtime follows the federal Fair Labor Standards Act (1.5× past 40 hours in a workweek) and, where chosen, the daily rules published by the California Labor Commissioner, the Alaska Department of Labor, the Nevada Labor Commissioner and the Colorado Division of Labor Standards and Statistics. Daily overtime hours are not counted again toward the weekly 40. These rules were last checked on 28 October 2026.
Date math is done in UTC so time zones and daylight saving time never shift a day. Business days skip Saturdays, Sundays and, if chosen, the 11 federal holidays in 5 U.S.C. 6103 on their observed dates.
By calculator
Corrections
If you find an error, tell us and it will be checked and fixed.