Time math is simple until it is not: midnight, leap years, weekend holidays and overtime rules. Here is how each tool handles them.
Our rules
- Everything runs in your browser. Nothing you type is sent to us. Lists you save stay on your device.
- Real calendars. Date tools use the actual calendar, with leap years.
- Holidays by the rule. Business-day tools use US federal holidays on their observed dates under 5 U.S.C. 6103, checked against OPM’s published list.
- Overtime with sources. The time card uses federal and state rules as published, and says what it leaves out.
- No guessing. Where a rule depends on your employer, contract or state, we say so.
Sources
- US Department of Labor: overtime under the FLSA (1.5 times the regular rate after 40 hours in a workweek; the workweek is a fixed 168-hour period)
- US Department of Labor, Wage and Hour Division Fact Sheet 23: Overtime Pay Requirements of the FLSA
- CalChamber: Understanding Overtime Pay in California (8 and 12 hour daily rules, 7th consecutive day)
- SHRM: Which states have daily overtime pay laws? (Alaska, California, Nevada, Puerto Rico and the Virgin Islands after 8 hours; Colorado after 12)
- US Office of Personnel Management: Federal Holidays
- OPM Handbook on Alternative Work Schedules, Appendix C: models of compressed work schedules (4-day week, 5/4-9 plan)
- 29 CFR 553.230: maximum hours for fire protection and law enforcement work periods under FLSA section 7(k)
- US Department of Labor Fact Sheet 8: Law Enforcement and Fire Protection Employees Under the FLSA
- Pomodoro Technique: 25-minute work intervals with short breaks and a longer break after four, developed by Francesco Cirillo
Last checked 1 November 2026.