A 24/48 never repeats on the same weekday
This is the single most important fact about planning custody around a Kelly-style rotation, and it is the one that catches people out. The cycle is three days long — one on, two off. Three does not divide by seven, so the pattern walks through the week: a Monday shift this week becomes a Thursday shift next week, then a Sunday. There is no arrangement built on named weekdays that survives this. Stop trying to find one.
| Week | On-shift days | What it does to a fixed plan |
|---|---|---|
| Week 1 | Mon, Thu, Sun | A "Tuesday and Wednesday" arrangement works |
| Week 2 | Wed, Sat | The same arrangement now collides with the Wednesday |
| Week 3 | Tue, Fri | It collides with the Tuesday instead |
What works instead is a plan written against the rotation — "the second off-day after each shift" — and then generated as real dates for the next three months and shared. The rule is what you and your co-parent agree; the dates are what everyone actually uses, including school and whoever covers the on-shift days.
The upside nobody mentions
Two full days off after every shift is a genuinely good deal for a parent, and often more usable time than a conventional job gives. A 24/48 delivers around twenty days off a month, in two-day blocks. If the plan is built properly, a firefighter can hold a substantial share of parenting time — considerably more than a Monday-to-Friday parent gets in practice. The obstacle is never the quantity of time. It is that it lands unpredictably against everyone else’s week.
What to put in the plan
Because the days move, the plan has to carry more written detail than a conventional one.
- The rule, in rotation terms. For example: the second off-day after each shift, plus the full off-block whenever it contains a weekend.
- Three months of generated dates. Refreshed whenever the roster changes. Nobody should be deriving a three-day cycle by hand.
- A named cover for on-shift days. Because your shift days move, the days needing cover move too. One agreed person is worth more than a general willingness to help.
- What happens on a held-over shift. A 24 becoming a 36 is not rare. Decide once whether the following block starts late or moves entirely.
- School dates checked against the rotation. Assemblies, parents’ evenings and trips are fixed; your availability is not. Check them against the rotation a term ahead.
Bottom line: A 24/48 runs on a three-day cycle that never lines up with the week, so write the plan in rotation terms and publish it as dates. Treat the whole 24 hours plus the following morning as blocked, and use the two-day off-blocks — there is more parenting time here than in most conventional jobs, if it is planned properly.