Sleep tracker
Log your nights in one click, calculate your cycles, track your 7-day sleep debt and your naps. No sign-up, no sensor: everything stays on your device.
The fast tool to track your nights, naps and habits. Everything stays on your device.
Log your bedtime then wake-up to see the detailed analysis.
How did you wake up?
Your tracking
No complete nights recorded.
History (Tap to edit)
Recent records
This tool does not provide a medical diagnosis. In case of chronic fatigue, severe insomnia or loud snoring, consult a healthcare professional.
Go deeper
Why track your sleep?
We spend roughly a third of our lives asleep. Yet few people actually know how many hours they sleep per night or whether their habits (coffee, screens, late workout) hurt their wake-ups. This tracker turns that blind spot into a few clear numbers: duration, cycles, regularity, accumulated debt.
Unlike standard apps: no account, no wristband, no data sent. Two clicks a day are enough — one at bedtime, one on waking — and the tool does the rest in your browser.
What you can track
Full nights
Bedtime, wake-up, total duration, perceived quality and number of awakenings.
Naps
Separate nap mode so they don't skew your main-night statistics.
Linked habits
Tag each night with late coffee, alcohol, screens in bed, sport or stress to see what really weighs.
Cycles and ideal wake times
Sleep is not measured in flat hours but in cycles of about 90 minutes (light, deep, REM). Waking at the end of a cycle feels much better than mid deep-sleep.
When you click "Bedtime", the tool instantly suggests 3 optimal wake times (4, 5 and 6 full cycles, +15 min to fall asleep) so you pick the one that fits your schedule.
The 7-day sleep debt gauge
On every entry, the tool computes:
- The total slept over the last 7 days.
- Your goal (6h to 9h per night, adjustable).
- A percentage showing if you are on track, slightly indebted or in critical debt.
- A concrete tip matched to the situation (move bedtime forward, take a nap, etc.).
Why 7 days? It's the window where you can still recover a deficit without disrupting metabolism. Beyond 14 days it becomes chronic deprivation.
Regularity: the often-forgotten metric
Many studies show that bedtime regularity matters as much as duration itself. The tool displays a 7-day regularity score and tells you whether you are "Stable", "Irregular" or "Very shifted". Great for spotting weekends that wreck the rhythm.
Full privacy
- Local save: everything stays in your browser (LocalStorage). No data leaves your device.
- Export / Import: save a JSON file to switch device or archive your data.
- Manual entry: forgot to click last night? Add the night after the fact in seconds.
Disclaimer: this tool is for personal tracking only. It does not provide a medical diagnosis. If you suffer from chronic fatigue, severe insomnia, loud snoring or sudden awakenings (possible signs of sleep apnea), consult a doctor or sleep specialist.
FAQ
Where is my sleep data stored?
Everything is kept locally in your browser's LocalStorage, on your device. Nothing is sent to our servers or any third party. You can export a JSON file at any time for backup or device migration.
What happens if I clear my browser cache?
Clearing the cache does not affect LocalStorage. However, "Clear all site data" does erase your recorded nights. Make sure to export your history as JSON regularly so you don't lose anything.
Can I sync my phone and my computer?
Not automatically, since we don't store anything online. The workflow is simple: export the JSON from the first device, transfer the file (email, AirDrop, cloud) and import it on the second device. The merge is instant.
What are the habit tags (coffee, screens, alcohol) for?
They help you spot which factors hurt or boost your nights. After a few weeks, comparing tags with perceived quality reveals patterns fast: coffee after 4pm, screens in bed, late workouts, etc.
How are sleep cycles computed?
A full cycle averages 90 minutes (light, deep, REM). The tool adds 15 minutes for falling asleep then suggests 4, 5 and 6 cycles from your bedtime. Waking at the end of a cycle is easier than mid deep-sleep.
How many hours of sleep should I aim for?
The average adult needs 7 to 9 hours per night. Teens and young adults rather 8-10h, seniors 7-8h. The default goal in the tool is 8h, but you can adjust it to your real need directly from the gauge.
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