What is a 9/80 Work Schedule and How Does it work?

In this article, we'll demystify the 9/80 work schedule, its origins, and mechanics. This guide will highlight the reasons for its implementation and considerations to ponder before adoption.

What is a 9/80 work schedule?

A 9/80 is a compressed biweekly pattern: employees work eight 9-hour days + one 8-hour day across two consecutive workweeks, then take one RDO (regular day off) every other week. The hallmark mechanic is the “split Friday”: you fix your FLSA workweek to start at the midpoint of that 8-hour Friday so each week totals 40 hours (no averaging across weeks).

Key guardrails (so it truly stays 40/40):

• Your workweek is a fixed, recurring 168 hours that can begin any day/any hour, but it cannot slide week to week to dodge overtime.

• Under the FLSA, each workweek stands alone; averaging hours over two+ weeks is not permitted. That’s why the split-Friday workweek start matters.

9/80 work schedule example

The 9/80 work schedule typically spans two weeks, with the work hours divided as follows:

ℹ️ Quick mental model: think of the 8-hour Friday as two 4-hour blocks—AM finishes Week A (reaching 40), PM starts Week B (on the way to 40). If someone starts early/late on that day, you can accidentally tip a week over 40.

Is it legal in 2025? 

Yes—if you align it to the FLSA’s workweek rules:

• Overtime trigger: Non-exempt employees earn OT for hours >40 in a fixed workweek at 1.5× their regular rate; the law applies week by week.

• Fixed workweek: Must be a constant 168-hour period; it may begin any day/hour but must stay consistent. Different teams may have different fixed workweeks.

• No two-week averaging: You can’t smooth a 44-hour week with a 36-hour week. Each week stands alone for OT.

⚠️State note: Some states add daily overtime or special rules. Your policy should say the company follows any stricter state/sector rules in addition to the FLSA.

👉 Manager tip: In your timekeeping/payroll system, lock the workweek start at the midpoint of the 8-hour Friday and restrict early/late clocking on that day; this avoids accidental >40 in the wrong week. The DOL’s own materials stress the fixed workweek and “no averaging” principles. 

United Kingdom: compressed hours under WTR (not a “9/80” law)

In the UK, “9/80” isn’t a statutory construct; it’s just a compressed hours arrangement that must respect the Working Time Regulations (WTR) and the updated flexible working regime.

What the law expects you to respect:

• Rest breaks & limits (WTR):

  • 20-minute uninterrupted break if working >6 hours in a day.

  • 11 hours daily rest between shifts.

  • 24 hours weekly rest (or 48 hours per 14 days).

• Flexible working (from 6 April 2024):

  • Day-one right to request flexible working; decision period shortened and process tightened (Acas Code updated). Use this when agreeing compressed hours patterns like 9/80-style weeks.

👉 Manager tip: Document the pattern, rest compliance, and review process in writing (policy + contract variation). Compressed hours are lawful provided you plan rosters to protect 11h daily rest and weekly rest, and you handle requests under the day-one flexible working framework.

Business cases & what results to expect

What actually moves for employers:

Who should avoid a 9/80?

• Teams with high fatigue/safety sensitivity (manufacturing, field operations, healthcare) where longer daily spans increase error or injury risk; consider shorter shifts or true hours reduction instead, then test. (Use your H&S data to decide; the four-day research highlights well-being gains when hours are reduced.)

• Organisations that cannot lock a fixed workweek in payroll/timekeeping (or that rotate it), this invites FLSA risk because the workweek must be fixed and recurring. 

• Units with frequent ad-hoc start/finish changes on the split-day (the 8-hour Friday). Even small shifts can spill hours into the “wrong” week and generate unintended overtime.

• UK teams that can’t guarantee WTR rest (11h daily, 24h weekly/48h per 14 days) due to customer coverage—compressed hours are lawful, but only if rosters preserve statutory rest. Also remember the day-one right to request flexible working since April 2024. 

Common pitfalls & how to avoid them

1. Split-Friday drift (classic).
   Employees start early, work through lunch, or swap RDOs; hours land in the wrong FLSA week → surprise OT.
   👉 Fix: Freeze the workweek start at the midpoint of the 8-hour Friday, restrict early/late clocking that day, and train managers on the split rule.

2. “We’ll average it over two weeks.”
   Averaging is not permitted under FLSA; each week stands alone.
   👉 Fix: Configure payroll to calculate OT weekly only; audit that the 40/40 split is preserved. 

3. Policy vagueness on holidays/PTO.
   9-hour vs 8-hour day credits create perceived inequity.
   👉 Fix: Write explicit rules (e.g., holidays credit 8 hours; employees top-up on 9-hour days or use 1 hour PTO). (Aligns with best-practice guidance in legal/HR explainers.)

4. UK implementation without WTR checks.
   Compressed hours that breach rest breaks invite risk.
   👉 Fix: Rota design must protect 11h daily rest and weekly rest; run it through the updated Acas Code process for flexible working requests.

Make 9/80 effortless with Shiftbase

Rolling out a 9/80 works best when scheduling, hours, and leave live in one place. Shiftbase ties it together so you can offer every-other-Friday off without blowing up coverage or payroll.

• Plan coverage and RDO rotations with drag-and-drop employee scheduling (clear rota views, teams/departments, instant updates).

• Capture accurate hours (including mobile and kiosk clock-ins) with time tracking so your 40/40 split actually holds in payroll.

• Apply fair, transparent leave rules for 9-hour vs 8-hour days using absence management (requests, policies, balances).

👉 Try it on your team: Start a free 14-day trial (no credit card). Pricing is transparent if you decide to stay.