Why the rule is shown
When someone disagrees with a timesheet, the argument is almost never about arithmetic. Everyone can multiply hours by a rate. The disagreement is about which rule applies: whether a long Tuesday counts, whether a rounded punch was rounded fairly, whether being salaried means overtime does not apply.
A calculator that returns a bare number is useless in that conversation. So every tool here states the rule it used — "Federal (FLSA) — over 40 in a workweek", "California — daily over 8, double over 12, seventh day" — and cites the source underneath. If the answer looks wrong, you can see which assumption to challenge.
How the logic is tested
The time and overtime logic is covered by an automated test suite that runs on every change: 119 assertions covering time parsing, shifts that cross midnight, rounding, daily and weekly overtime for each supported state, pay splits, federal holiday dates and pay schedules.
Two of those tests exist because the mistakes they catch are easy to make and hard to spot:
- Pyramiding. Five ten-hour days in California is fifty hours — forty regular and ten overtime. A calculator that applies the daily rule and then the weekly rule to the same hours reports twenty, which is double, and looks entirely plausible.
- Overnight shifts. An end time earlier than the start time means the shift crossed midnight, not that the day was negative.
Holiday dates are computed rather than typed in, including the rule that a fixed-date holiday on a Saturday is observed the Friday before and one on a Sunday the Monday after. A hardcoded list would be wrong the moment the year changed.
What these tools are not
- Not legal advice. They apply published rules to numbers you supply. If you believe you have been underpaid, your state labour department takes complaints and it costs nothing.
- Not payroll software. Pay figures are gross — before income tax, payroll tax and deductions.
- Not complete on state law. Only states with a genuinely different daily overtime rule are modelled. Inventing variation for the rest would be inventing precision.
How this is paid for
Display advertising on the pages. The tools are free, there is no account, and nothing is held back behind a paid tier. No employer, payroll provider or law firm has any influence over what these tools say — which matters, because most pages ranking for these questions are published by companies selling payroll software.
Privacy
Calculations run in your browser. Your hours, rate and dates are not sent anywhere, because there is no server to send them to. Your last settings are kept in your own browser's storage so you do not retype them, and clearing your browser data removes them.
Contact
Corrections matter more here than anywhere else on this site — if a rule is wrong, the number is wrong. Reports are welcome via the contact page, and a citation to the statute or regulation gets a fix fastest.