How to Keep a Sleep Diary: What to Record and How to Read It

By KT Apps · Updated October 16, 2026

Why keep a sleep diary

Writing down a few facts each morning turns a vague feeling ("I never sleep well") into something you can actually look at. After a couple of weeks you can see your typical bedtime, how much it drifts at weekends, and whether bad nights have anything in common, such as late caffeine, screens in bed or a stressful day.

A diary is also handy if you decide to talk to a doctor about your sleep. Clinicians often ask people to keep one, because a written record of real nights is more reliable than a description from memory.

A sleep diary is a personal record, not a diagnosis. If you are often exhausted during the day, snore loudly, stop breathing or gasp at night, or have trouble sleeping for weeks at a time, speak to a doctor.

What to record each morning

Fill it in soon after you get up, while the night is still fresh. Keep it short enough that you will actually do it every day:

• The date the night belongs to. Pick one rule (for example, the date you went to bed) and stick to it.
• Bedtime: the time you got into bed intending to sleep.
• Wake time: the time you got up for the day, not the first time you opened your eyes.
• Sleep quality on a simple scale, such as 1 (very bad) to 5 (very good).
• How you felt before bed and after waking, on the same scale.
• A short note about anything unusual: caffeine or alcohol in the evening, exercise, a late meal, travel, illness, noise or worry.

Some paper diaries also ask how long it took to fall asleep and how many times you woke. Those are estimates at best, so only add them if you find them useful. Estimating is fine; nobody watches the clock all night, and you should not try to.

A simple sleep diary template

If you prefer paper, rule a page into columns like this and fill in one row per night:

• Date | Bedtime | Wake time | Hours | Quality (1-5) | Before bed (1-5) | After waking (1-5) | Notes
• Example: Mon 14 | 23:15 | 06:45 | 7.5 | 3 | 2 | 3 | Coffee at 4 pm, work deadline

Work out the hours from bedtime to wake time. When the night crosses midnight, count up to midnight and then on to the wake time; how to calculate hours of sleep shows the arithmetic with examples.

How long to keep it

One night tells you almost nothing. Aim for at least one to two weeks, so the diary includes both workdays and days off. That is usually enough to see your normal rhythm, the gap between weekday and weekend sleep, and whether the bad nights cluster.

If you are trying a change, such as an earlier bedtime or no caffeine after lunch, keep the diary going for a couple of weeks before and after. Changes in sleep are often small and slow, and a single good night is not proof that something worked.

How to read the patterns

Average duration

Add up the hours and divide by the number of nights. Compare it with how you feel during the day rather than with a single magic number; needs differ from person to person.

Consistency

Look at how much your bedtime and wake time move around. A wake time that jumps by two or three hours between weekdays and weekends is common and is one of the easiest things to notice in a diary.

Quality versus hours

Check whether your low-quality nights are also your short nights, or whether some long nights still feel poor. The notes column often explains the difference.

Before and after

Comparing how you felt before bed with how you felt after waking shows whether nights tend to leave you better or worse. A pattern of waking up feeling worse is worth paying attention to.

Paper, spreadsheet or app?

Paper

Easy to start and easy to hand to a doctor. You have to do the duration sums and averages yourself, and it is hard to see trends at a glance.

Spreadsheet

Formulas can calculate durations and averages and draw a chart, but setting them up takes time, and overnight times need care. It is also less convenient to fill in from bed.

Sleep diary app

Quick to fill in on a phone and does the calculations for you. Choose one that keeps the entry short, so the habit survives the second week.

Wearables

Trackers estimate sleep from movement or heart rate without you typing anything, but the readings are estimates and do not record how you felt or what happened that day. Many people find a written diary useful alongside one.

Keeping a sleep diary in Sleeplog

Sleeplog is a manual sleep diary: no sensors, just the entries you type.

1. On the Record tab, choose the date the night belongs to.
2. Enter your bedtime and wake time. Sleeplog calculates the duration, including nights that cross midnight.
3. Use the sliders to rate your condition before sleep, your condition after waking and the sleep quality, each from 1 (very bad) to 5 (very good).
4. Add a note about caffeine, exercise, stress or anything else, then press Save.
5. Open the History tab to see past nights. Tap one to view, edit or delete it.
6. On the Analysis tab, choose 7 days, 14 days, 1 month, 3 months or all to see average sleep time, average quality, average mood change, a chart of hours slept and your best night.

In the web version your entries stay in this browser on this device, with no account. Sleeplog is also available for iPhone and Android.

Frequently asked questions