Last 7 nights actual sleep
Hours you actually slept each night
Recovery plan
Sleep +1 hr for 11 nights, or +30 min for 21 nights, to clear the deficit.
Research caveat: a single 12-hour weekend sleep doesn't fully fix chronic weeknight debt — the cognitive recovery is gradual.
By night
- 7 nights ago7h−1h
- 6 nights ago6.5h−1.5h
- 5 nights ago7h−1h
- 4 nights ago6h−2h
- 3 nights ago7.5h−0.5h
- 2 nights ago6h−2h
- Last night5.5h−2.5h
Frequently asked questions
Partially. A 2016 University of Chicago study found that 3 nights of recovery sleep restored most cognitive markers, but not all — chronic deficit causes inflammation and metabolic changes that take weeks to undo. The lesson: small daily deficits compound. Catching up on weekends doesn't fully fix five weeknights of 5-hour sleep.
The American Academy of Sleep Medicine and the National Sleep Foundation both recommend 7-9 hours for adults 18-64. Some genetic outliers thrive on 6 — they're rare (~1% of the population). For everyone else, claiming to function on 5-6 hours usually means functioning while sleep-deprived, not adapting to less sleep.
A 20-30 minute nap reduces sleepiness for the next few hours and is genuinely restorative for alertness. It does NOT replace night sleep for memory consolidation, hormone regulation, or long-term cognitive recovery. Treat naps as a top-up, not a substitute.
The calculator measures deficit, not blame. If your situation forces a deficit, you can use this to: (a) see how big the deficit really is, (b) plan recovery on off-days, and (c) discuss with your doctor if you're consistently >2 hours below target. Shift workers carry a chronic deficit measurable in this tool.
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