Who builds it
My Hours Math is built and maintained by Ali Nawaz, a software developer who has built websites and web tools for businesses since 2017. I started it because the free time card calculators I tried either hid the tool behind ads, got overnight shifts wrong, or couldn't give me a clean file to hand to a manager.
How the calculators are tested
The time math runs in your browser from one small engine with automated tests: overnight shifts (10 PM to 6 AM is 8 hours), lunch taken as a clock-out and clock-in or as minutes, quarter-hour rounding at the 7-minute mark, federal weekly overtime, California daily overtime and the seventh-day rule, biweekly periods with overtime worked out per workweek, and the 8 and 80 system. Every change has to pass those tests before it goes live.
Where the rules come from
Overtime and break rules are taken from the official sources, linked on each page: the U.S. Department of Labor and the Code of Federal Regulations for federal rules, and each state's labor department for state rules. When a rule changes, the page and the calculator are updated together and the page shows the date it was last checked.
What the calculators are for
They help you check your own hours and pay, fill in a time card, or prepare figures for payroll. They give estimates. Your employer's records, your employment agreement and the law that applies to your job decide what you are actually paid. If something looks wrong, raise it with your employer first, and for a dispute, contact your state labor department or the U.S. Department of Labor's Wage and Hour Division.