FLSA Workweek Definition: How Your 7-Day Clock Is Set

What the FLSA Workweek Actually Is

The Department of Labor defines a workweek as a fixed and regularly recurring period of 168 hours, which is seven consecutive 24-hour periods. That is the whole definition. It is short, but every word does work.

Fixed means the starting point does not move. Once set, it stays put. Regularly recurring means it repeats on the same schedule, week after week, without exception.

The workweek does not have to match the calendar week. It can begin on any day and at any hour. A workweek that starts Wednesday at 7 a.m. and runs to the following Wednesday at 6:59 a.m. is completely valid.

The workweek is fixed even when your schedule isn’t

Per 29 CFR 778.105, once a workweek is established it stays fixed regardless of the hours actually worked. Your shifts can move around inside that 168-hour window all they want. The window itself does not budge.

That is the point of the rule. The workweek is a stable measuring stick, and your hours are what get measured against it.

Why 168 hours, not just “a week”

Calling it 168 hours instead of “a week” removes ambiguity by pinning the period down to the hour. That precision matters when a shift crosses midnight or straddles the boundary between one workweek and the next, because the exact start time decides which week those hours belong to.

Workweek vs. Pay Period vs. Calendar Week

This is the single biggest source of confusion for hourly workers, so it is worth slowing down. Three different things often get treated as one.

The three terms, untangled

• Calendar week: Sunday through Saturday. A convention, not a legal term for overtime.
• Pay period: how often you get paid, whether weekly, biweekly, semimonthly, or monthly. A scheduling choice your employer makes for payroll.
• Workweek: the fixed 168-hour window the FLSA uses to count overtime. The only one of the three that decides your 41st hour.

They can overlap. They are still not the same. Your workweek might start Monday, your pay period might also start Monday, and Monday might be a normal calendar day. None of that makes the three concepts identical.

Why this trips people up

Most workers are paid biweekly, so they think in 80-hour blocks. But overtime is never calculated over 80 hours in a pay period. It is calculated over 40 hours in each of the two separate workweeks that make up that pay period.

Per DOL Fact Sheet #23, each workweek stands alone. Averaging hours over two or more weeks is not permitted for overtime or minimum wage purposes.

So if you worked 36 hours in the first workweek and 44 in the second, you are owed 4 hours of overtime for the second week. The fact that 36 plus 44 equals 80, a “normal” two-week total, does not erase that overtime. The light week cannot be used to cancel out the heavy one.

How Your Employer Sets and Documents the 7-Day Clock

The FLSA gives the employer the right to choose the workweek. The employee does not get a vote. But that choice comes with rules.

The employer picks the start

Your employer decides which day and which hour the workweek begins. Common choices are Sunday at midnight or Monday at 12:01 a.m., but nothing requires those. A 24-hour operation might pick Friday at 6 a.m. so the boundary falls during a slow shift.

Different groups can have different workweeks

Under 29 CFR 778.105, an employer may establish different workweeks for different employees or groups of employees. The warehouse crew might run a Monday workweek while the office runs a Sunday workweek. Each group’s window still has to be fixed and regularly recurring.

The workweek has to be documented

This is the part that protects you. DOL Fact Sheet #21 on recordkeeping requires covered employers to keep a record of the time of day and day of the week the workweek begins. The employer cannot keep it secret or make it up after the fact.

How to find yours

You have three reliable places to look:

• The employee handbook. The workweek is frequently spelled out in the pay or timekeeping section.
• HR or payroll. Ask directly, and ask for the answer in writing. They are required to know it.
• Your pay stub. Many stubs print the workweek start and end dates next to the hours.

If nobody can give you a straight answer, that is itself a warning sign. The workweek is a required record, and a vague answer is worth following up on.

Why the Start Day Changes Your Overtime

Here is the part most articles skip: a worked example showing the same hours producing different overtime depending only on where the 7-day boundary falls.

The setup

Say you work the following daily hours across two weeks, paid at $20/hour:

• Mon: 8   Tue: 8   Wed: 8   Thu: 8   Fri: 12   Sat: 4   Sun: 0
• Then the next stretch: Mon: 10   Tue: 10   Wed: 8   Thu: 6   Fri: 0   Sat: 0   Sun: 0

Scenario A: workweek starts Monday

Week 1 (Mon to Sun) totals 8 + 8 + 8 + 8 + 12 + 4 + 0 = 48 hours. That is 8 overtime hours.

Week 2 (Mon to Sun) totals 10 + 10 + 8 + 6 = 34 hours. No overtime.

Total overtime: 8 hours.

Scenario B: workweek starts Friday

Now the boundary falls before Friday. The first workweek captures Friday 12, Saturday 4, Sunday 0, then Monday 10, Tuesday 10, Wednesday 8, Thursday 6 = 50 hours. That is 10 overtime hours.

The remaining days (Monday 8, Tuesday 8, Wednesday 8, Thursday 8 from the first stretch) fall into a different workweek and total 32 hours. No overtime.

Total overtime: 10 hours.

Same hours, different paycheck

The exact same shifts produced 8 overtime hours under one boundary and 10 under another. At $20/hour, the half-time premium difference is 2 hours x $10, or $20 for that stretch. Over a year, a boundary that consistently splits your heavy days favorably (or unfavorably) adds up.

This is not a loophole you can use, since the employer sets the boundary. But it is exactly why you should know where yours sits, and why a tool like the overtime calculator only gives the right answer when you feed it the correct week-start day.

Can Your Employer Change Your Workweek? Your Rights

Yes, a workweek can be changed, but the FLSA puts a fence around it so the change cannot become a pay cut in disguise.

The permanent-change rule

Per 29 CFR Part 778, the beginning of the workweek may be changed if the change is intended to be permanent and is not designed to evade the overtime requirements of the Act.

Two conditions, both required. The change has to be meant to stick, and it cannot be a maneuver to shrink your overtime.

What “evading overtime” looks like

An employer who slides the workweek boundary forward and back from week to week, conveniently splitting your heavy days so neither week tops 40, is evading overtime. That is not allowed. The whole reason the workweek must be fixed is to block this exact move.

A genuine, one-time, permanent shift is fine, for example moving from a Sunday start to a Monday start to match a new payroll system.

The dual-calculation transition rule

When the workweek changes, some hours unavoidably overlap the old and new windows. The FLSA handles this with a protective rule: the employer must compute the overtime for the overlapping period both ways, under the old workweek and under the new one, and pay you the greater amount.

You never lose money in the transition. If the change happens to land in your favor, you keep that benefit. If it would shortchange you, the old calculation protects you.

What to do if a change looks wrong

Ask payroll, in writing, when the change took effect and how the overlap week was calculated. If overtime dropped right after the change, ask them to show both calculations. If the answers do not add up, you can file a confidential complaint with the DOL Wage and Hour Division at dol.gov/agencies/whd/contact/complaints or call 1-866-487-9243.

How to Track Your Own Workweek and Check the Math

Once you know where your 7-day clock starts, verifying your pay is straightforward. The trick is logging your hours against the same boundary your employer uses.

Step 1: Confirm your week-start day

Get it from the handbook, HR, or your stub. Write it down. Everything else depends on this one fact being right.

Step 2: Log hours to that boundary

Track every shift and group it by your real workweek, not the calendar week and not the pay period. A timecard that starts on the wrong day will quietly miscount your overtime. Setting the week-start day inside Timeclock44 lets you log hours against the exact 7-day window your employer uses, so your running total matches theirs.

Step 3: Total each workweek separately

Add the hours in each 7-day window on its own. Do not combine two weeks. Any single workweek over 40 hours owes overtime on the excess.

Step 4: Compare against your stub

Match your per-workweek totals to the regular and overtime lines on your pay stub. If your records show 44 hours in a workweek and the stub shows 40 regular and 0 overtime, you have a documented gap to raise.

Step 5: Keep the records

Save your logs and your stubs. If you ever need to talk to payroll or the DOL, contemporaneous hour records are the strongest evidence you can bring. For the overtime math itself, see our guide to the regular rate of pay, since the rate you multiply matters as much as the hours you count.