Sleep Debt Calculator

Calculate your sleep debt based on ideal vs actual sleep hours. Track your sleep deficit over time.

The arithmetic is deliberately plain: your nightly target minus your actual average is the per-night shortfall, and that shortfall multiplied by the number of days you enter is the accumulated total. Eight hours against a 6.5-hour average gives 1.5 hours a night and 10.5 hours over a week. Two details matter for reading it correctly. First, the two hour fields carry identical weight — each is a single term in a subtraction, so trimming your target by half an hour and finding an extra half hour of actual sleep produce exactly the same improvement. Second, the accumulated row is labelled Weekly Sleep Debt but the window is whatever day count you supply, anywhere from 1 to 365; set it to 30 and the "weekly" figure reports 45 hours, which is a month. Behind the scenes the tool also scales the total by 4.33 to approximate a calendar month, a figure the results panel does not surface. The status label is graded on the accumulated total rather than the nightly gap, switching to Mild above zero, Moderate above 3 hours and Severe above 7 — which means a modest 1.5-hour nightly shortfall reads Severe once seven days have compounded it. Sleeping longer than your target is allowed and produces negative numbers with a Well Rested label. What the model omits is everything about sleep quality: fragmentation, apnoea, timing relative to your body clock, and the well-documented fact that recovery sleep repays debt only partially, not hour for hour.