4 on / 4 off Shift Calendar

Four on, four off is an 8-day cycle of 12-hour shifts. It's simple and predictable, but because eight doesn't divide into seven, your days off rotate through every weekday over time. Four crews cover the clock: A and B alternate on days, C and D alternate on nights.

About the 4 on / 4 off schedule

Four on, four off is an 8-day cycle of 12-hour shifts. It's simple and predictable, but because eight doesn't divide into seven, your days off rotate through every weekday over time. Four crews cover the clock: A and B alternate on days, C and D alternate on nights.

Who works it: Emergency services, security, manufacturing and offshore work.

Cycle length
8 days
Shift length
12 hours
Crews
4 (A and B days, C and D nights)
Days worked per year
~182
Weekends
Rotates

Common questions

What does “cycle start date” mean?

The first day your crew works at the beginning of the rotation. If you're not sure, pick any day you know you were on shift and adjust it until the calendar matches a month you remember.

Can I change the colours?

Yes. The swatches under the pattern picker set a colour per crew or shift — A green, B blue and C red to start with. Change one and it stays that way in your browser next time. Every day also carries its shift code, so the calendar still makes sense printed in black and white or read by someone who is colour blind.

How do I get this on my phone?

Click Download .ics and open the file. iPhone and Android will both offer to add it to your calendar, with every working day as an all-day entry.

Is it free?

Yes, and there's no account to make. The calendar is built in your browser and nothing you generate is uploaded or kept — the site never learns anything about you.