90 Minute Timer
A 1 hour 30 min countdown timer with sound alert. Press start to begin.
Presets
About the 90 minute timer
Ninety minutes is the length of a full football match, a feature film and one complete ultradian rhythm cycle — the roughly 90-minute wave of alertness and fatigue your brain runs on during the day.
What you can do in 90 minutes
- One full ultradian cycle of deep work, followed by a real break
- A full football match, film or long training session
- Braising a tough cut of meat until it is tender
- A long-form writing or design session without context switching
90 minutes at a glance
| Seconds | 5400 s |
| Hours | 1.50 h |
| Share of one hour | 150% |
| Share of a 24-hour day | 6.25% |
| Full blocks in an 8-hour workday | 5 |
| Full blocks in 24 hours | 16 |
| Equivalent 25-minute Pomodoros | 3.6 |
Tip: Schedule your hardest thinking inside one 90-minute window per day, and stop when it ends — trying to push past the cycle usually produces tired, low-quality work.
Frequently Asked Questions
How long is a 90 minute timer?
A 90 minute timer runs for 90 minutes, which equals 5400 seconds or 1.50 hours — 150% of an hour.
What can I do in 90 minutes?
One full ultradian cycle of deep work, followed by a real break; A full football match, film or long training session; Braising a tough cut of meat until it is tender; A long-form writing or design session without context switching.
How many 90-minute blocks fit in an 8-hour workday?
An 8-hour workday holds 5 full 90-minute blocks; a full day holds 16.
Is the 90 minute timer free and does it make a sound?
Yes — free, no registration, no download, and it plays an alert at zero. Everything runs locally in your browser.