Free · No sign-up · Works in the background
90 Minute Timer
90 minutes of deep work, then a 20-minute break. Press Start, keep this tab open, and it chimes when the block is done.
Space starts and pauses. Esc skips a break. Want breaks without keeping a tab open? Peeka does this on your Mac.
How to use this timer
- Pick one hard thing and press Start. Close what you don't need. Leave this tab open.
- Rest your eyes along the way. 90 minutes is a long time to stare at a screen, so look far away every 20 minutes. The 20-20-20 timer in a second tab will remind you.
- When it chimes, take the full 20 minutes. Away from the screen. The next block starts on its own.
The 90-minute rhythm at a glance
| Work | 90 minutes |
|---|---|
| Break | 15 to 30 minutes. This timer uses 20 |
| Based on | Sleep researcher Nathaniel Kleitman's idea of a basic rest-activity cycle of about 90 minutes (80 to 120) that continues through the day |
| Evidence | Solid for sleep cycles. Disputed for daytime focus since 1977 |
| Good for | Writing, coding, design: work that takes a while to get into |
| Less good for | Routine tasks, or days when you can't protect a 90-minute block. Try the 25 minute timer. |
Where the 90 minutes come from
Nathaniel Kleitman, the sleep researcher who co-discovered REM sleep, noticed that sleep runs in cycles of about 90 minutes. In his 1963 book Sleep and Wakefulness he proposed that a similar cycle, 80 to 120 minutes long, carries on through the day as waves of alertness and fatigue. He called it the basic rest-activity cycle.
Productivity writers later turned it into a work rhythm: focus for about 90 minutes, then rest before the next wave.
Does it work?
Be a little careful with the science. The 90-minute cycle in sleep is well established. Whether the same cycle drives focus during the day is less clear: as early as 1977 a paper titled "There's no basic rest-activity cycle" argued there was no evidence for it outside sleep, though later studies did find daytime rhythms of roughly this length. We couldn't find a study that tests 90-minute work blocks against shorter ones.
The practical case is better. Hard creative work takes time to warm up, and a 90-minute block leaves room for that. A 2022 review of break studies also found that demanding work benefits from longer breaks, which is why this timer gives you 20 minutes rather than 5.
What to do with 20 minutes
- Leave the screen behind. After 90 minutes your eyes need distance more than anything.
- Move. Walk outside, climb some stairs, do a few stretches.
- Eat or drink something away from your desk.
- Don't start a new task. Email counts as a task.
Compare the rhythms
| Rhythm | Work / break | Good for | |
|---|---|---|---|
| 20-20-20 | 20 min / 20 sec | Your eyes. Tiny breaks, often. | Open |
| Pomodoro | 25 min / 5 min, long break after four | Getting started, studying, work you've been avoiding. | Open |
| 50/10 | 50 min / 10 min | Lining work up with the hour and your meetings. | Open |
| 52/17 | 52 min / 17 min | Long focus with a break long enough to leave the desk. | Open |
| 90/20 | 90 min / 20 min | Deep work with a slow warm-up: writing, coding, design. | This page |
| Flowmodoro | As long as focus lasts / a fifth of that | Work where being cut off mid-flow costs you. | Open |
| Animedoro | 40 to 60 min / one 20-minute episode | Studying, with a show as the reward. | Open |
Want your own lengths? The break timer takes any work and break time.
Peeka for Mac
A browser tab can't tell when you're busy. Peeka can.
Peeka is a tiny ghost that lives on your Mac's desktop and does this timer's job without a tab to keep open. It gets sleepier as your break gets closer, so the break never takes you by surprise.
- Waits until you stop typing, so it never cuts you off mid-sentence
- Hides during calls, presentations and screen shares
- Dims your screen for 20 seconds and gives you something to look at
- Naps when you step away, and starts fresh when you're back
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FAQ
Questions, answered.
Does the timer keep running if I switch tabs?
Yes. It keeps time against the clock, so it stays accurate in a background tab, and it remembers where it was if you reload. If your browser puts unused tabs to sleep to save memory, pin this tab.
How will I know it's break time?
You'll hear a soft chime, and you'll get a desktop notification if you allow them. If the tab is in front, a dim blanket slides over the page and counts the break for you.
Isn't 90 minutes too long without a break?
For your attention, it can work if the task is absorbing. For your eyes, it's long. Look at something far away every 20 minutes during the block, or run the 20-20-20 timer in another tab.
What is an ultradian rhythm?
A body rhythm that repeats more than once a day. The best-known one is the roughly 90-minute sleep cycle. Kleitman's idea was that a similar rhythm continues while you're awake.
Can I combine it with Pomodoro?
Yes. Some people work in three 25-minute rounds with short breaks, then take a longer break, which adds up to a 90-minute block.
Does it work on my phone?
It runs in any modern browser, but phones lock their screens and pause web pages, so it works best on a laptop or desktop.
Is it really free?
Yes. No sign-up and no ads. It's made by Sameed, who also makes Peeka, a Mac app that does the same job without a browser tab.