⏱️ Focus Cadence Reference
Focused work comes in whole units of focus-plus-rest, so capacity moves in steps rather than smoothly. This grid shows what each cadence fits into a given window, and how much time is left unallocated — every figure computed by the same function behind the Ultradian Cycle Planner.
| Window | 90 / 20 unit 110 min | 60 / 15 unit 75 min | 50 / 10 unit 60 min | 25 / 5 unit 30 min |
|---|---|---|---|---|
| 2h 120 min | 1 × 90min 90 focused · 75% 10 min spare | 1 × 60min 60 focused · 50% 45 min spare | 2 × 50min 100 focused · 83.3% exact fit | 4 × 25min 100 focused · 83.3% exact fit |
| 3h 180 min | 1 × 90min 90 focused · 50% 70 min spare | 2 × 60min 120 focused · 66.7% 30 min spare | 3 × 50min 150 focused · 83.3% exact fit | 6 × 25min 150 focused · 83.3% exact fit |
| 4h 240 min | 2 × 90min 180 focused · 75% 20 min spare | 3 × 60min 180 focused · 75% 15 min spare | 4 × 50min 200 focused · 83.3% exact fit | 8 × 25min 200 focused · 83.3% exact fit |
| 5h 300 min | 2 × 90min 180 focused · 60% 80 min spare | 4 × 60min 240 focused · 80% exact fit | 5 × 50min 250 focused · 83.3% exact fit | 10 × 25min 250 focused · 83.3% exact fit |
| 5h30 330 min | 3 × 90min 270 focused · 81.8% exact fit | 4 × 60min 240 focused · 72.7% 30 min spare | 5 × 50min 250 focused · 75.8% 30 min spare | 11 × 25min 275 focused · 83.3% exact fit |
| 6h 360 min | 3 × 90min 270 focused · 75% 30 min spare | 4 × 60min 240 focused · 66.7% 60 min spare | 6 × 50min 300 focused · 83.3% exact fit | 12 × 25min 300 focused · 83.3% exact fit |
| 7h 420 min | 3 × 90min 270 focused · 64.3% 90 min spare | 5 × 60min 300 focused · 71.4% 45 min spare | 7 × 50min 350 focused · 83.3% exact fit | 14 × 25min 350 focused · 83.3% exact fit |
| 8h 480 min | 4 × 90min 360 focused · 75% 40 min spare | 6 × 60min 360 focused · 75% 30 min spare | 8 × 50min 400 focused · 83.3% exact fit | 16 × 25min 400 focused · 83.3% exact fit |
Reading the grid
The extra hour that buys nothing. At 90/20, a 4h window gives 2 cycles and 180 focused minutes. A 5h window gives the same 2 cycles and the same 180minutes — the entire extra hour lands in the leftover column, which grows from 20 to 80 minutes. The third cycle does not arrive until 330 minutes. Before negotiating for more time, check which side of a boundary you are on.
Units that divide into hours never waste anything.50/10 and 25/5 have units of 60 and 30 minutes, so they fit every round window exactly — look down those two columns and the leftover is zero throughout. 90/20’s 110-minute unit divides into almost nothing, which is why it shows 80 and 90 minutes spare on five- and seven-hour days. Its one clean fit here is 5h30, where it takes 90 / 20 to zero leftover and an 81.8% focus ratio.
The focus ratio has a ceiling.Whenever a cadence fits exactly, its ratio is just focus divided by unit — 25/30 for 25/5, which is why that column reads 83.3% over and over. No amount of scheduling pushes a cadence above its own ratio; the only way up is a longer focus block relative to its rest, and that trades against how well you hold the block.
What the grid cannot see: the cost of starting. Every cycle boundary pays a reload cost — getting the problem back into your head — and shorter cadences pay it more often. For work with a long warm-up that cost can exceed the leftover minutes this table is optimising. Treat the grid as the arrangement question and your own work as the answer to which arrangement suits it.
Where each cadence gains a cycle
- 90 / 20 (unit 110 min) — 1 cycle at 110 min, 2 cycles at 220 min, 3 cycles at 330 min, 4 cycles at 440 min, 5 cycles at 550 min
- 60 / 15 (unit 75 min) — 1 cycle at 75 min, 2 cycles at 150 min, 3 cycles at 225 min, 4 cycles at 300 min, 5 cycles at 375 min
- 50 / 10 (unit 60 min) — 1 cycle at 60 min, 2 cycles at 120 min, 3 cycles at 180 min, 4 cycles at 240 min, 5 cycles at 300 min
- 25 / 5 (unit 30 min) — 1 cycle at 30 min, 2 cycles at 60 min, 3 cycles at 90 min, 4 cycles at 120 min, 5 cycles at 150 min
Windows just below a boundary are the ones to be suspicious of; windows just above one are the ones worth protecting hardest, because a small interruption there costs a whole cycle rather than a few minutes.
❓ Frequently Asked Questions
Why does an extra hour sometimes add no focused work at all?
Because capacity comes in whole units of focus plus rest, not in minutes. At the 90/20 cadence the unit is 110 minutes, so a four-hour window fits 2 cycles (180 minutes of focus, 20 left over) and a five-hour window fits exactly the same 2 cycles — the whole extra hour becomes leftover, taking it from 20 to 80 minutes. The third cycle does not appear until 330 minutes.
Which cadence wastes the least time?
The one whose unit divides into the window you actually have. 50/10 and 25/5 have units of 60 and 30 minutes, so they fit any round number of hours with nothing left over. 90/20 has a 110-minute unit, which divides into almost no ordinary window — it is the most wasteful on a five-hour or seven-hour day, and the neatest on a five-and-a-half-hour one.
So is the shortest cadence always best?
No — the grid only measures arrangement. Short blocks pay the start-up cost more often, and for work with a long warm-up that cost is real and invisible here. The table tells you what each cadence costs in leftover minutes; whether those transitions cost you more than the leftover does is something only your own work can answer.
Where do these numbers come from?
They are computed, not typed in. Each cell calls the same planner function behind the cycle planner and prints what it returns. A test asserts every cell still equals a fresh call to that function, so this table cannot drift away from the tool.