Last updated: March 2026
Frequently Asked Questions
How is sleep deficit different from sleep debt?
They're the same concept — the gap between how much sleep you need and how much you actually got. 'Deficit' implies ongoing, 'debt' implies accumulated. This tracker handles both: a 7-day window showing your current deficit and the compounded debt.
What's considered a severe sleep deficit?
Under 6 hours/night for several consecutive nights places you in a 'severe' zone where cognitive performance measurably degrades, immune function weakens, and metabolic health markers worsen. Chronic severe deficits (weeks or months) correlate with long-term health risks.
Should I use sleep tracking apps alongside this?
Yes — if you have an Apple Watch, Oura Ring, Whoop, or Fitbit, enter the total hours each device reports. Those devices measure sleep architecture (REM, deep, light) which this tool does not. Use them together for a complete picture.