Free tool · no sign-up
Sleep calculator
Plan a bedtime or wake time around full 90-minute sleep cycles, then check your real weekly sleep debt. Runs entirely in your browser.
Weekly sleep-debt tracker
Enter the hours you actually slept each of the last 7 nights. The tracker adds up the shortfall against an 8-hour-per-night baseline.
Frequently asked questions
How does the bedtime planner pick times?
It works backward (or forward) from your target time in 90-minute sleep cycles — the widely-cited average length of one full light/deep/REM cycle — plus a 14-minute buffer for the time it typically takes to actually fall asleep. Waking up near the boundary between cycles, rather than mid-cycle, is associated with feeling less groggy.
Why does it show more than one time?
Everyone’s cycle length varies a bit, and more cycles is not strictly better past a point — 5 cycles (7.5h) and 6 cycles (9h) are both reasonable targets depending on your age and how rested you already are. The calculator shows a range centered on the generally-recommended 7–9 hours for adults so you can pick what fits your schedule.
What counts as "sleep debt"?
Sleep debt here is the cumulative shortfall between the hours you actually slept each night and an 8-hour baseline, added up across the week you enter. It is a rough, widely-used proxy, not a medical measurement — persistent large debt is worth addressing with actual recovery sleep, not just awareness.
Does this connect to Bump’s smart alarm?
Not directly — this page is a standalone, no-account browser tool. Bump’s own smart alarm reads real on-device motion and snore-detection data to generate sleep insights automatically, which this page cannot do without the app.