90 Minute Timer
1:30:00
Ninety minutes is the block people reach for when the work has a long approach — a proof, a chapter, a difficult refactor. It is also roughly the length of the body’s natural rest-activity cycle, which is a popular justification and a much weaker one than it is usually presented as.
What 90 minutes is good for
- Problems that take twenty minutes just to load
- A morning block before anything else touches the day
- Writing that needs continuity to hold together
- Work you would rather not stop in the middle of
Where it falls down
Only works on a protected day. Ninety minutes with two interruptions is worse than forty-five without any, and most days contain the interruptions.
Using it well
Name one task before you press begin — not a subject but a task, the kind of thing that can be finished or not finished. Put the phone in another room rather than face down; the difference between silenced and requiring you to stand up is the whole intervention. And stop mid-sentence when it rings, because returning to an obvious next keystroke is far easier than returning to a blank page.
If you set the timer and then still do not start, the problem is not the length. It is the crossing, and no timer configuration fixes that — a timer has nothing to say about whether you began. That is what body doubling is for.
Common questions
- Is the ninety-minute cycle real?
- The ultradian rhythm is a real observed pattern in sleep, and its extension to daytime focus is a popular idea with much thinner evidence than the confident articles suggest. Ninety minutes is a good long block for practical reasons; treat the biology as a story rather than a reason.
- What break does a ninety-minute block need?
- Fifteen to twenty minutes, genuinely away. After a block this long the break is recovery, not a pause — going straight into another one produces a second block worth much less than the first.
Other lengths
- Online timers
Working timers for every focus length, with the honest case for each one.
- ADHD Timer
A free ADHD-friendly visual timer with 5, 10, 20 and 25-minute starts, ambient sound and no account. Start small, then continue if focus arrives.
- 5 Minute Timer
A five-minute timer that runs in your browser. Five minutes is the length you use when the task is not the problem — starting is.
- 10 Minute Timer
A ten-minute timer that runs in your browser. Long enough to finish something small, short enough to agree to on a bad day.
- 15 Minute Timer
A fifteen-minute timer that runs in your browser. The standard unit for admin, tidying, and anything you have been putting off.
- 20 Minute Timer
A twenty-minute timer that runs in your browser. A gentler alternative to the standard pomodoro, and often a better fit.