Eight hours. With a 30-minute unpaid lunch, seven and a half. The math is simple once you see it, but a surprising number of people end up Googling this every Monday morning. Here's every standard shift, plus the history of how 9-to-5 became the default.
| Shift | Without lunch break | With 30-min lunch | With 60-min lunch |
|---|---|---|---|
| 9 AM – 5 PM | 8.0 hours | 7.5 hours | 7.0 hours |
| 8 AM – 5 PM | 9.0 hours | 8.5 hours | 8.0 hours |
| 9 AM – 6 PM | 9.0 hours | 8.5 hours | 8.0 hours |
| 7 AM – 3 PM | 8.0 hours | 7.5 hours | 7.0 hours |
| 7 AM – 4 PM | 9.0 hours | 8.5 hours | 8.0 hours |
| 10 AM – 6 PM | 8.0 hours | 7.5 hours | 7.0 hours |
| 10 AM – 7 PM | 9.0 hours | 8.5 hours | 8.0 hours |
| 8:30 AM – 4:30 PM | 8.0 hours | 7.5 hours | 7.0 hours |
| 8:30 AM – 5:30 PM | 9.0 hours | 8.5 hours | 8.0 hours |
The 9-to-5 workday isn't ancient — it's a 20th-century invention, mostly American, and traces directly to one company: the Ford Motor Company.
In 1914, Henry Ford halved the standard workday from 16 hours to 8 hours, doubled wages from $2.34 to $5, and discovered something interesting: workers were more productive, less likely to quit, and could actually afford to buy his cars. By 1926, Ford had also adopted a 5-day workweek. Within a decade, most US industries followed suit.
The Fair Labor Standards Act of 1938 codified 40 hours per week as the federal overtime threshold, locking in the pattern. 9 to 5 became the shorthand: 8 hours of work + 1-hour lunch = 9 hours at the office. Dolly Parton turned it into a movie title in 1980.
Yes, in most cases. Under FLSA in the US, meal breaks of 30+ minutes are typically unpaid as long as the employee is fully relieved of duty. Short rest breaks (5–20 minutes) are typically paid. Some states (Massachusetts, California) have specific rules requiring paid breaks under certain conditions.
If you're eating lunch at your desk while taking calls, that's working time, even if you call it "lunch." Time when you're free to leave the premises is genuinely break time.
The Hours Calculator handles any combination of start time, end time, and break minutes — including overnight shifts and split shifts. The Quick mode shows the answer for a single shift; the Weekly mode builds out a full timesheet.
Last updated May 2026. If something here is wrong or out of date, email contactus@calculatehours.net — we update fast.