Sleep Calculator
Not all naps are equal. A 20-min power nap boosts alertness without grogginess. A 90-min full cycle includes REM sleep for memory consolidation. Find your ideal nap window.
Boosts alertness, no grogginess. Best for a quick recharge.
Includes REM sleep. Best for memory & creativity. Allow 15 min to wake up fully.
Micro-nap. Reduces sleepiness fast with minimal sleep inertia.
How it works
This sleep calculator runs entirely in your browser — no data is sent to any server. Simply fill in the fields above and the result updates instantly. You can copy the output with the copy button provided.
Frequently Asked Questions
How does the sleep cycle calculator work?
Sleep occurs in 90-minute cycles. Waking up at the end of a cycle (rather than mid-cycle) makes you feel more rested. The calculator adds 14 minutes for average sleep onset.
How many sleep cycles should I get?
Most adults feel best with 5–6 full sleep cycles (7.5–9 hours). Teenagers need more — typically 6–8 cycles.
What time should I go to bed to wake up at 6am?
To wake at 6:00am feeling refreshed, go to sleep at 8:46pm, 10:16pm, 11:46pm, or 1:16am — each being a full number of 90-minute cycles before your wake time.
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