Log your nights, see the pattern

Free sleep diary: the simplest sleep tracker there is

A sleep diary is the original sleep tracker. Long before wearables, sleep clinics asked patients to write down when they went to bed, when they woke and how they felt. Our free online sleep diary does the same in a few taps: add the night's bedtime and wake-up time, rate how rested you feel, and see a seven-day chart with your average sleep, average bedtime and how much your timing varies.

If you are searching for a "free sleep tracker", "sleep tracker app that actually works" or an "online sleep monitor", a diary is a good place to begin. It costs nothing, has no subscription and needs no hardware. It also gives you something a watch cannot: your own judgement of how the night felt.

How to use the sleep diary

Each morning, enter the date, the time you went to bed, the time you woke up, and a one to five rating for how rested you feel. Save the entry and the chart updates. After a few days you will see patterns: the nights you went to bed late, the mornings you slept in, and the link between a late bedtime and a low rating. Keep going for two weeks for a reliable picture. If you miss a day, you can add it later; there is no streak to break.

What the numbers mean

Average sleep shows the time between bedtime and wake-up over the last seven nights. Remember that time in bed is not time asleep, so if you take a long time to fall asleep, your true sleep is shorter. Average bedtime and wake-up time show your typical schedule. Bedtime varies by measures regularity: a spread under 45 to 60 minutes is good, and a larger spread suggests the schedule itself may be affecting how you feel.

Sleep diary versus a sleep tracker app or wearable

A wearable measures movement and heart rate to estimate when you slept and, with less certainty, which stage you were in. It does this without effort, which is its main advantage. A diary requires you to remember but records the thing the device cannot know: when you actually got into bed, how you felt, and what happened that day. Many sleep specialists still ask for a diary even when the patient owns a watch. Our guide to the best sleep tracker explains the trade-offs, and the page on free sleep tracker apps lists app options.

Why clinicians use sleep diaries

Cognitive behavioural therapy for insomnia, which is the recommended first treatment for long-term insomnia, relies on a sleep diary for one to two weeks before and during treatment. The diary identifies patterns such as long periods awake in bed or irregular timing, and it measures progress. You can use the same approach at home, though if your sleep problem is severe or lasts more than a month, ask your doctor for help.

Private by design

Entries are stored in your browser and never leave your device. There is no account, no ads based on your data and no export to third parties. The trade-off is that data does not sync between devices, and clearing your browser data erases it. See the privacy page for more, and visit My sleep to view all your saved settings in one place.

Turning diary data into action

Once you have a week of entries, look for the biggest gap. If your average sleep is below your need, plan an earlier bedtime with the bedtime calculator or check the sleep debt calculator. If your bedtime varies, choose a fixed wake-up time. If your ratings are low on nights after late caffeine, try the caffeine cutoff. If your pattern is late by nature, take the chronotype quiz.

What to write in your sleep diary

Log the time you got into bed, the time you woke, and a quick rating of how rested you feel. If you want more detail, keep a separate note for caffeine, alcohol, exercise, late meals and unusual events. You do not need to be exact: nearest 10 or 15 minutes is fine. Write it down within an hour of getting up, before the night becomes hazy.

Reading your seven-day chart

The chart shows one bar per night. Look for two things: nights that are much shorter than the rest, and a ragged edge on the bedtime side. Short nights call for an earlier bedtime. A ragged bedtime calls for a steadier schedule. If your ratings are low on nights when you slept the same length as on good nights, something other than duration, such as alcohol, stress or noise, is likely involved.

Keeping up the habit

The best time to fill in the diary is when you brush your teeth or make your first drink. Keep the page open on your home screen, or install the site so it is one tap away. If you skip a day, move on; missing entries do not spoil the pattern. After two weeks you will have enough data to see which habits matter most.

Sleep diaries in cognitive behavioural therapy for insomnia

In CBT-I a diary is used to calculate sleep efficiency, the percentage of time in bed spent asleep, and to set a sleep window. A therapist may tighten the window for a short period to build sleep pressure, then widen it as efficiency improves. This approach, known as sleep restriction, should be supervised by a trained clinician, because it can cause daytime sleepiness at first. If you think it might suit you, bring your diary to a doctor.

Privacy checklist for any diary

Whether paper, app or online, think about who can read it. Our version stores everything in your browser and shares it with no one. On a shared computer, remember that someone else using the same browser profile can see it. Use the delete button on My sleep when you finish, or keep a private browser profile.

Frequently asked questions