Sleep Calculator
Recommended bedtimes
* Includes 15 minutes to fall asleep
Frequently Asked Questions
Everything you need to know about sleep cycles
What is a sleep cycle?
A sleep cycle lasts about 90 minutes and includes 4 phases: light sleep (N1, N2), deep sleep (N3/slow waves) and REM (dreaming). Waking up at the end of a cycle, when sleep is lightest, reduces feelings of tiredness and confusion (sleep inertia).
How many cycles do you need for good sleep?
Most adults need 5-6 cycles per night (7.5-9 hours). Sleeping 4 cycles (6 hours) is the acceptable minimum. Fewer than 4 cycles leads to cumulative sleep deprivation that impacts concentration, mood and long-term health.
Why does it take time to fall asleep?
On average it takes 10-20 minutes to fall asleep. If it takes less than 5 minutes you are probably sleep deprived. The tool uses 15 minutes as the default but you can customize it. Sleeping in dark, cool and quiet environments reduces sleep latency.
Does my data stay private?
Yes, and not because we promise it: this tool runs entirely inside your browser. What you type or upload never leaves your device, so it never reaches a server of ours and there is nothing we could keep, read or lose. You can check it yourself: open the page, disconnect from the internet, and the tool keeps working.
Do you store what I enter?
No. There is no database behind this tool: we do not store your files, your text or your results. When you close the tab nothing is left — not here with us, because it never arrived, and not anywhere else.
Do you profile me? Are you GDPR compliant?
We do not profile you: there is no account to create, we never ask for your email to use a tool, and we keep no profile of what you do. We are an Italian company and we work under the GDPR and the other European rules, with the privacy notice and the consent request in plain sight. One thing we say in full rather than hiding it behind a slogan: the ads on the page are Google's, and Google may use cookies to personalise them. You decide from the consent banner: if you say no the ads stay, but they are not personalised, and the tool works exactly the same.
If it is free, how do you make money?
From the ads on the page, and that is all. We do not sell your data, there is no hidden paid plan, there is no limit that eventually asks for your card, and you do not have to sign up. The ads pay for the servers and for the time we spend writing the tools: that is how we can keep them open to everyone.