HitchDaysShort answer
A 21/7 rotation schedule is 21 days at work followed by 7 days off, repeating every 28 days. In Australian FIFO rosters it is written 3/1, three weeks on and one week off. 28 days is exactly four weeks, so every hitch starts on the same weekday. You work three quarters of the year, about 274 days, and go home 13 times a year for a week each time.
How a 21/7 adds up
| Question | Answer for 21/7 |
|---|---|
| Full cycle | 28 days (4 weeks): 21 on, 7 off |
| Share of the year at work | Three quarters |
| Days on per year, on average | 273.9 (365.25 x 21 / 28) |
| Days on in one calendar year | 273 to 274 |
| Trips home per year | 13 |
| Crew change on the same weekday? | Yes, always |
21/7 works the most days of the common rotations: about 30 more a year than a 2 and 1 (14/7), and about 91 more than an even-time 14/14. Its cycle is the same length as a 14/14, 28 days, so the crew change lands on the same weekday and the hitches start on the same dates as a 14/14 that started on the same day; only the split inside the 28 days differs.
A worked 21/7 calendar from November 2026
First hitch day Wednesday, November 4, 2026. Day 21 is Tuesday, November 24; the first home day is Wednesday, November 25; the next hitch starts 28 days after the first, on Wednesday, December 2.
Swipe the table sideways to see every column.
| Hitch | On hitch (days 1 to 21) | Home (days 1 to 7) |
|---|---|---|
| 1 | Wed Nov 4 to Tue Nov 24 | Wed Nov 25 to Tue Dec 1 |
| 2 | Wed Dec 2 to Tue Dec 22 | Wed Dec 23 to Tue Dec 29 |
| 3 | Wed Dec 30 to Tue Jan 19, 2027 | Wed Jan 20, 2027 to Tue Jan 26, 2027 |
| 4 | Wed Jan 27, 2027 to Tue Feb 16, 2027 | Wed Feb 17, 2027 to Tue Feb 23, 2027 |
| 5 | Wed Feb 24, 2027 to Tue Mar 16, 2027 | Wed Mar 17, 2027 to Tue Mar 23, 2027 |
| 6 | Wed Mar 24, 2027 to Tue Apr 13, 2027 | Wed Apr 14, 2027 to Tue Apr 20, 2027 |
| 7 | Wed Apr 21, 2027 to Tue May 11, 2027 | Wed May 12, 2027 to Tue May 18, 2027 |
| 8 | Wed May 19, 2027 to Tue Jun 8, 2027 | Wed Jun 9, 2027 to Tue Jun 15, 2027 |
| 9 | Wed Jun 16, 2027 to Tue Jul 6, 2027 | Wed Jul 7, 2027 to Tue Jul 13, 2027 |
| 10 | Wed Jul 14, 2027 to Tue Aug 3, 2027 | Wed Aug 4, 2027 to Tue Aug 10, 2027 |
| 11 | Wed Aug 11, 2027 to Tue Aug 31, 2027 | Wed Sep 1, 2027 to Tue Sep 7, 2027 |
| 12 | Wed Sep 8, 2027 to Tue Sep 28, 2027 | Wed Sep 29, 2027 to Tue Oct 5, 2027 |
| 13 | Wed Oct 6, 2027 to Tue Oct 26, 2027 | Wed Oct 27, 2027 to Tue Nov 2, 2027 |
| 14 | Wed Nov 3, 2027 to Tue Nov 23, 2027 | Wed Nov 24, 2027 to Tue Nov 30, 2027 |
Reading it: this crew is home for Thanksgiving (November 26 is home day 2) and Christmas (home day 3), then flies back on December 30, so New Year's Day is day 3 of a hitch. Memorial Day and July 4, 2027 both fall on hitch days. With only one week home in four, which holidays land at home depends entirely on the first hitch day.
The same three months, colored the way HitchDays colors them:
November 2026
December 2026
January 2027
- Hitch days
- Home days
Open this example in the rotation calculator and change the first hitch day to yours.
How to work out your own 21/7 dates
Find one first hitch day you're sure of, and settle whether the fly-in day counts as day 1.
Add 21 for the first home day. The day before is day 21, the last day on site.
Add 28 for each next hitch, which is the same weekday four weeks later.
Check one past date you remember against your list.
In a spreadsheet, with the first hitch day in B1 and a date in A2: =IF(MOD(A2-$B$1,28)<21,"Hitch","Home").
Common mistakes on a 21/7
- Reading 3/1 as days. In a FIFO roster 3/1 means weeks: 21 days on, 7 off.
- Losing the week home to travel. If flights come out of your 7 days, you may have 5 or 6 nights at home. Check how your roster counts fly-in and fly-out days.
- Mixing up 21/7 and 21/21. 21/21 is even time, three weeks home. 21/7 is one week home.
- Calling the first hitch day day 0. If day 1 is November 4, day 21 is November 24.
Questions about 21/7 rotations
What does 21/7 mean?
21 days at work, then 7 days off, repeating every 28 days. It is the same roster as 3/1, three weeks on and one week off, written in days instead of weeks.
How many days a year do you work on a 21/7?
About 274: three quarters of the year. Because the cycle is short, every calendar year holds 273 or 274 work days.
Does a 21/7 always start on the same day of the week?
Yes. The cycle is 28 days, exactly four weeks, so if one hitch starts on a Wednesday, they all do.
How is 21/7 different from 14/7?
Both give one week at home. 14/7, also called 2 and 1, has two weeks of work before it in a 21-day cycle, about 243 work days a year. 21/7 has three weeks of work in a 28-day cycle, about 274.
Keeping a 21/7 on your iPhone
HitchDays, the iPhone app this site is for, takes a custom rotation of 21 days on and 7 off. Give it one first hitch day and it colors every month and shows the days until you're home on the first screen and in a free Home Screen widget. It works with no signal, which matters on a remote site.