Your workweek can start on any day and at any hour, but it has to be fixed and repeat. It does not have to match the calendar week or your pay period.
Each workweek stands alone. If you work 48 hours one week and 32 the next on a two-week check, you are owed 8 hours of overtime, even though the total is 80. An employer cannot shift the workweek around to avoid overtime.
The minimum wage make-up for tipped workers is also checked per workweek, so one slow week is not erased by a busy one. Ask payroll what day your workweek starts if the stub does not say.
Check your own paycheck
Enter your stub and your hours. The checker applies your state's rules and shows anything that is short, with the rule behind it. Nothing you type leaves your browser.