What sleep debt means here: For each night below your selected target, the calculator adds the difference to the accumulated shortfall. For example, sleeping two hours below target on each of seven nights produces a 14-hour shortfall.
Why extra sleep is shown separately: A night above target reduces the week's net difference, but the calculator does not claim that it automatically cancels every cognitive, metabolic, or circadian effect of previous short sleep.
The three totals:
Age-based starting ranges: The calculator uses 9–12 hours for ages 6–12, 8–10 for ages 13–18, 7–9 for ages 19–64, and 7–8 for ages 65 and older. Individual sleep need varies, so the selected target remains adjustable.
Planning illustration: The 3-, 5-, and 7-night figures simply divide the net weekly shortfall across that many nights. They are schedule arithmetic, not a prescription or a prediction of biological recovery.
Research sources: See the NHLBI explanation of accumulated sleep debt, the AASM pediatric sleep-duration consensus, the National Sleep Foundation duration recommendations, and research on recovery from chronic sleep restriction.
Privacy and history: No login is used. Completed calculations are stored only in this browser. Changing or clearing inputs without calculating saves nothing.