A week has 168 hours — 7 days times 24 hours — but a work week is a much smaller number, and it depends on what kind of schedule you are on. The standard full-time work week in the United States is 40 hours, usually five 8-hour days. Part-time weeks run anywhere from under 20 hours to just below 40, and shift schedules reach the same totals by different routes: four 10-hour days also make 40, and three 12-hour days make 36. This guide lays out the totals for each pattern, so a weekly-hours question has an answer you can check rather than guess.

First, the two different “hours in a week”

There are 168 hours in a calendar week, full stop: 7 × 24. Nobody works all of them. The work week is the slice of those 168 hours spent working, and the standard slices are what this guide is about. When someone asks “how many hours in a week” without context, they usually mean one of two things: the 168-hour calendar total, or the 40-hour full-time work week. If they ask “how many hours in a work week,” the answer is 40 for a standard full-time schedule, with part-time and shift patterns below it.

Full-time patterns that add up to 40

Paid totals assume the lunch is unpaid where stated. A 9-to-5 week with an unpaid lunch is 37.5 paid hours, not 40 — the missing 2.5 hours are the week’s lunches.

The 40-hour week is also the overtime line under US federal law: hours over 40 in a week are overtime for non-exempt workers. That is why the 8-to-5-with-lunch pattern at 42.5 hours and the six-day pattern at 48 hours both cross into overtime, while the 37.5-hour pattern does not. Some states add a daily line too — overtime after 8 hours in a day — which is why a single 10-hour day can earn overtime even inside a 40-hour week. The Hours Calculator shows both the weekly and the daily overtime totals so you can see which rule bites.

Part-time and short-week patterns

There is no single legal definition of part-time in hours; under 40 is the usual working meaning, and many employers draw their own benefits line around 30 hours.

Shift basics: 8-hour, 10-hour, and 12-hour shifts

An 8-hour shift is the default unit of a work week: five of them make 40, and the classic 9-to-5 shift is an 8-hour span that pays 7.5 hours after an unpaid lunch. A 9-to-5 shift lasts 8 hours on the clock — the span from 9am to 5pm — and the paid portion is 8.0 or 7.5 depending on whether lunch is paid. A 10-hour shift compresses the week: four of them make 40 with a weekday free, at the cost of longer days that can cross a daily overtime line in states that have one. A 12-hour shift is the hospital and factory standard: three of them make 36 hours — technically part-time by the 40-hour line, usually treated as full-time by the employer — and four make 48, well into overtime territory.

Rotating shifts complicate the weekly total because the same worker’s hours differ week to week. The honest way to answer “how many hours do I work in a week” on a rotation is to total each week separately and average over the rotation cycle: a two-week rotation of 40 hours then 32 hours averages 36 hours a week, even though neither individual week is 36. A weekly-hours calculator helps here only if you enter each week on its own; averaging the schedule first and then multiplying is how rotation totals go wrong.

How to work out your own week

For each day, take clock-out minus clock-in, subtract unpaid breaks, and add the days. That is the method the Hours Calculator applies across a whole timesheet, and our guides to hours between two times and work hours with lunch deducted work the day-level math in full. If your schedule is set by a rota rather than fixed days, total the rota week itself — the days printed on it — rather than assuming five identical days.

Totals: calendar week 7 × 24 = 168 hours; US federal overtime line 40 hours in a week (FLSA); daily overtime rules and part-time thresholds vary by state and employer.