A sleep diary is a brief record of your nights and days. It can help you explain a pattern without relying on memory alone. NHLBI suggests keeping one for one to two weeks before an appointment about insomnia. [source]
What to record
NHLBI’s guidance includes bed and wake times, naps, daytime tiredness, caffeine and alcohol, and exercise. [source] You can keep the record in a notebook or use the printable template linked below.
| Field | What to write |
|---|---|
| Night and morning | Bedtime, estimated time to fall asleep, awakenings, final wake time |
| Daytime experience | Naps, tiredness and a brief description of how you felt |
| Context | Caffeine, alcohol, exercise and unusual events |
| Personal observation | A sound, a room change or anything you want to discuss |
An illustrative entry
Friday night: went to bed around 23:00. Took a while to settle. Woke after a door closed and once more for no clear reason. Got up around 07:00. Felt tired in the afternoon. Had coffee later than usual and worked late.
This is a fictional example of the level of detail to aim for. It does not identify the cause of the tiredness. “Not sure” is a useful entry when you cannot remember.
Keep estimates honest
You do not need to watch the clock through the night to fill in the diary. Write what you remember in the morning and label uncertain times as estimates. If you forget a day, leave a gap. Filling it with guessed detail can make the record harder to interpret.
Keep the format stable while you use it. Add a new field only if it answers a question you care about. If you are trying a bedtime sound, for example, record which sound and whether you left it playing; a detailed rating system is unnecessary.
Use the record for a conversation
Look for observations you want to discuss: a change in schedule, repeated disruption or daytime difficulty. Bring the notes to an appointment and describe what matters most to you. Let the clinician decide whether further assessment is appropriate.
Sources and further reading
- Insomnia: DiagnosisNHLBI / NIH. Updated 24 March 2022; sleep diary and assessment guidance.
Prepared by Dozemere. Sources checked on 24 October 2026. How we write about sleep.