How to use a 90-minute focus session
A 90-minute session is made for deep work: studying where you need to hold a lot in your head at once, like writing a long essay, working through hard maths or learning a difficult topic from scratch. You focus for 90 minutes, then take a proper 20-minute break.
- Plan the session before you start. Decide what you want to finish in the next 90 minutes and add it to your task list.
- Remove distractions. Ninety minutes is a long time to resist your phone, so put it in another room and close everything you don't need.
- Focus until the timer ends. It's normal for the first 10–15 minutes to feel slow. Most people find their concentration deepens after that.
- Take a real 20-minute break. Get up, eat something, go outside. After three sessions, the timer gives you a 30-minute break.
Why 90 minutes?
The idea is linked to ultradian rhythms: cycles of roughly 90 minutes that sleep researcher Nathaniel Kleitman observed during sleep and suggested might continue through the day. The evidence for a fixed 90-minute cycle while awake is mixed, but many people find 90 minutes a natural length for one deep block of work, with time to warm up and still get a lot done.
Is a 90-minute session right for you?
Long sessions work best once you're used to focusing for extended periods. If you're new to timed study, or your concentration is low today, start with the 25/5 Pomodoro timer or the 50/10 timer and build up. Two or three 90-minute sessions a day is plenty for most people; the quality of your focus matters more than the number of hours.
Frequently asked questions
Is it good to study for 90 minutes straight?
For many people, yes, as long as you take a real break afterwards. Ninety minutes gives you time to get into a difficult task and make real progress. If your focus fades well before the end, shorter sessions will probably serve you better.
How long should a break be after 90 minutes of study?
Around 15–20 minutes is a common choice. This timer uses 20 minutes by default, plus a 30-minute break after every three sessions. You can change both in Settings.
Can I change the session lengths?
Yes. Open Settings to adjust the focus, short break and long break lengths and how many sessions come before a long break. Your lengths for this page are saved in your browser.
Does the timer keep running in a background tab?
Yes. The timer is based on the clock, so it stays accurate if you switch tabs. When a session ends it plays a chime and, on browsers that support it, shows a notification.