9/80 Work Schedule: How Overtime Works

Disclaimer: This article is for educational purposes only and is not tax, legal, or financial advice. Overtime rules change and vary by state; always check current Department of Labor guidance, your state labor agency, or a qualified professional.

What a 9/80 Schedule Actually Is

A 9/80 schedule packs 80 work hours into nine days instead of ten. You work eight 9-hour days, one 8-hour day, and take one day off every two weeks. That extra day off is usually a Friday, which is why people call it an “every other Friday off” schedule.

Line it up over two weeks and it looks like this:

Week 1: Monday through Thursday at 9 hours each, plus 8 hours on Friday.
Week 2: Monday through Thursday at 9 hours each, plus Friday off.

Nine working days, 80 hours, one long weekend every fortnight. For salaried exempt workers, none of this matters. Overtime rules only apply to non-exempt (hourly) employees, so this whole article is written for them. If you are not sure which bucket you fall in, our guide on exempt vs. non-exempt employees sorts that out first.

Almost nobody explains the part that actually matters. A 9/80 only avoids overtime because of an accounting move buried in federal law. Understand that move and you can check whether your own paycheck is right.

Why a Normal 9/80 Would Owe Overtime Every Cycle

Overtime under the Fair Labor Standards Act is a weekly rule. The FLSA requires 1.5x the regular rate for every hour worked over 40 in a single workweek. There is no federal daily overtime. What matters is the seven-day total.

Now count a 9/80 the naive way, with a normal Sunday-to-Saturday calendar week:

Week 1: four 9-hour days (36) plus one 8-hour Friday = 44 hours. That is 4 overtime hours.
Week 2: four 9-hour days (36) plus Friday off = 36 hours.

Add both weeks and you get 80 hours of work. But the FLSA does not let you average two weeks together. Week 1 blew past 40, so 4 hours of overtime are owed, even though Week 2 came in under. A straight 9/80 on a calendar week owes 4 overtime hours every single cycle.

Employers do not want to pay that. So they use a trick to make both weeks land at exactly 40.

The Mid-Shift Workweek Split That Makes It Legal

The trick lives in one regulation, 29 CFR 778.105. A workweek is a fixed, regularly recurring period of 168 hours, or seven consecutive 24-hour days. And here is the loophole: it does not have to match the calendar. It can start on any day, at any hour, as long as it stays fixed.

So the employer sets the workweek to begin in the middle of the 8-hour day, usually at noon on Friday. That single boundary cuts the 8-hour Friday in half and drops each half into a different workweek.

Walk it through with a noon-Friday start:

The first 4 hours of the 8-hour Friday (8 a.m. to noon) fall at the end of the closing week. That week already had 36 hours from Monday through Thursday. 36 + 4 = 40.
The last 4 hours of that same Friday (noon to 4 p.m.) fall at the start of the opening week. That week then adds four 9-hour days. 4 + 36 = 40.

Both weeks hit exactly 40. No overtime. The 80 hours split cleanly into two 40-hour buckets, and the schedule stays legal.

The catch is that this boundary is invisible. It sits in the middle of a Friday shift and never shows up as a line on most timesheets. You clock in Friday morning like any other day. Nothing on your card announces that noon is the seam between two workweeks. That invisibility is why the overtime it can trigger is so easy to miss.

How a Long Lunch or a Few Extra Hours Quietly Triggers Overtime

The 40/40 split only holds if every hour lands where it is supposed to. The math balances on a knife edge. Move a few hours across that noon-Friday line and one week tips over 40.

Here are the ways it breaks:

A long lunch on the split Friday. Your lunch runs 30 minutes over, so you stay until 4:30 p.m. to finish 8 worked hours. Those extra 30 minutes of work now sit after noon, in the opening week.
Clocking in early or staying late on any 9-hour day. An extra 45 minutes on a Tuesday pushes that week past its planned 36 or 40.
Working on your “off” Friday. Get called in for even 2 hours on the week you were supposed to be off, and that 36-hour week climbs.
Swapping which day is the 8-hour day. If the short day moves off Friday, the split no longer lines up with the workweek boundary at all.

A worked example

Say your workweek starts noon Friday, and on the split Friday your lunch runs long, so you work noon to 5 p.m. instead of noon to 4 p.m. That is 5 worked hours after noon instead of 4.

Opening week: 5 hours (Friday afternoon) + 36 hours (Mon–Thu) = 41 hours.
That is 1 overtime hour owed at 1.5x your regular rate.

If you earn $28 an hour, your regular rate sets the overtime premium at roughly $14 extra for that hour on top of straight time. One hour does not sound like much. But a payroll system running a fixed 9/80 template often assumes every week is exactly 40 and never recalculates. The extra hour worked gets paid at straight time, and the half-time premium quietly goes missing.

Do this a few times a month and it adds up. Our overtime calculator will compute the premium once you know a week crossed 40, and the back-pay calculator will total what you are owed across several cycles.

The California Trap: Daily Overtime and the AWS Vote

Everything above is federal law. California rewrites the rules, and this is where a lot of 9/80 workers get shorted without realizing it.

California pays overtime on a daily basis. Under the state daily overtime rules, non-exempt workers earn 1.5x for hours over 8 in a workday, and double time over 12. Every 9-hour day on a 9/80 has a 9th hour. That hour is over 8. Under the plain daily rule, it is overtime.

So how do California employers run 9/80 schedules at all? Through a formal Alternative Workweek Schedule, or AWS. A valid AWS lets a work unit adopt longer daily shifts without triggering daily overtime, but only if the employer follows every step:

A written proposal describing the schedule.
A pre-election meeting held at least 14 days before the vote.
A secret-ballot vote of the affected work unit.
Two-thirds approval of the employees in that unit.
Reporting to the California DIR within 30 days.

Miss any step and the AWS is not valid. And here is the problem: a lot of California employees on a 9/80 have never voted on anything. They were simply put on the schedule. If there was no proper vote, the schedule may have no legal standing, and every 9th hour on those 9-hour days is owed at 1.5x, with hours past 12 at 2x.

If you are in California, ask a direct question: was there ever a secret-ballot vote on this schedule, and was it filed with the state? If the answer is no or nobody knows, your 9-hour days may owe daily overtime.

California is not alone. Alaska, Nevada, and Colorado also have daily overtime rules with their own thresholds. The overtime rules by state tool shows what applies where you work.

How to Check Your Own 9/80 Paycheck

You do not need a payroll degree to audit a 9/80. You need your defined workweek boundary and a few minutes. Here is the process.

1. Find your workweek start. Ask HR or payroll for the exact day and time your workweek begins. This is the single most important number, and most workers have never been told it. On a 9/80 it is almost always mid-shift on the 8-hour day (like noon Friday).

2. Rebuild both weeks around that boundary. Split the 8-hour day at the boundary and drop each half into the correct week. A biweekly timecard calculator lets you lay out the full two-week cycle, and the compressed work week calculator is built for exactly this schedule.

3. Total each week and flag anything over 40. If either week crossed 40, overtime is owed for the hours above 40 in that week, no matter what the two-week total says.

4. If you are in a daily-overtime state, count daily hours over 8. In California, confirm a valid AWS actually exists. No AWS means every 9th hour is likely overtime.

5. Reconcile against your pay stub. Compare the overtime hours you calculated to the overtime line on your stub. A gap is your evidence.

6. Raise it, then escalate if needed. Bring your rebuilt weeks to payroll first. Most 9/80 shortfalls are template errors, not fraud, and get fixed once someone points them out. If payroll won’t fix it, our guide on filing a wage claim for unpaid hours walks through the next step, and back pay and the statute of limitations covers how far back you can recover.

The hard part of all this is logging the split day to the minute. That is where a tracker that mirrors the 9/80 structure earns its keep. Timeclock44 lets you set a per-job week-start day, which maps directly to the FLSA workweek boundary that makes a 9/80 work, and it subtracts breaks from worked hours so a long lunch on the split Friday shows up in the right week instead of hiding. Export the record to PDF or CSV and you have a clean paper trail for any dispute.

9/80 vs. 4/10: A Quick Comparison

People often weigh a 9/80 against a 4/10 schedule, so it helps to see the difference. A 4/10 is four 10-hour days every week, with three days off each week and no mid-shift split needed, because each week already sits at exactly 40 hours. A 9/80 spreads nine days across two weeks with every other Friday off, and it leans entirely on the workweek split to stay at 40/40.

The 4/10 is simpler and harder to break. The 9/80 gives you a three-day weekend only every other week, but keeps a more normal daily length. For the full breakdown, see our companion post on the 4/10 compressed workweek and overtime.

Frequently Asked Questions

Does a 9/80 schedule avoid overtime?

Yes, but only because the employer defines the workweek to start mid-shift on the 8-hour day, splitting it so each week totals exactly 40 hours. If that boundary isn’t set (or your hours drift), overtime is owed.

How does the workweek split work on a 9/80 schedule?

The 7-day FLSA workweek is set to begin partway through the 8-hour day (commonly noon Friday). The first half of that day counts toward the closing week and the second half toward the opening week, so neither week exceeds 40 hours.

Can a long lunch on the 8-hour day trigger overtime?

Yes. If your lunch runs long or your hours shift on the split day, worked time can land on the wrong side of the workweek boundary, pushing one week past 40 and creating owed overtime.

Is a 9/80 schedule legal in California?

Only with a formally adopted Alternative Workweek Schedule (written proposal, secret-ballot vote, 2/3 approval, DIR filing). Without a valid AWS, each 9-hour day owes daily overtime for the hour over 8.

How many hours is a 9/80 schedule?

80 hours over a two-week cycle: eight 9-hour days, one 8-hour day, and one day off — nine working days instead of ten.

What’s the difference between a 9/80 and a 4/10 schedule?

A 4/10 is four 10-hour days each week (three days off weekly); a 9/80 is nine days across two weeks with every other day off. The 9/80 relies on a mid-shift workweek split to avoid OT; a 4/10 stays at 40 hours per week without one.

Do I get overtime for the 9-hour days on a 9/80?

Not under federal law as long as each workweek stays at 40 hours. In daily-overtime states like California, yes — every hour over 8 per day is overtime unless a valid AWS is in place.

How do I check if my 9/80 paycheck is correct?

Find your employer’s defined workweek start, rebuild both weeks around that boundary, total each week (flag anything over 40), count daily hours over 8 if you’re in a daily-OT state, and reconcile against your pay stub.

References

29 CFR 778.105: Determining the Workweek — Federal regulation defining the fixed, recurring 168-hour workweek that a 9/80 split relies on.
U.S. Department of Labor: Overtime Pay — Official overview of the FLSA’s over-40-per-workweek overtime rule.
DOL Fact Sheet #23: Overtime Pay Requirements of the FLSA — Details on how overtime is calculated on a workweek basis.
California DIR: Overtime FAQ — California’s daily and weekly overtime rules for non-exempt employees.
California DIR: Exceptions to the General Overtime Law — Requirements for a valid Alternative Workweek Schedule.