Calculators
Sleep Debt Calculator
Calculate weekly sleep debt by comparing nightly sleep with your sleep need, and the average shortfall per night.
- Runs in your browser
- Nothing uploaded
The tool
Enter your numbers below. Results update as you type, and nothing leaves your browser.
Everything you enter stays on your own machine. Nothing is sent to us or to anyone else, which you can confirm in your browser network tab.
What people use it for
- Tracking sleep habits
- Planning recovery after busy weeks
- Wellbeing programmes
- Shift work planning
About this tool
What the Sleep Debt Calculator does
Sleep debt is the gap between the sleep you need and the sleep you get. Most adults need seven to nine hours a night. Adding up each night’s shortfall over a week shows how much sleep is missing and whether it is a pattern worth fixing.
Formula
- Nightly shortfall = sleep need − hours slept
- Sleep debt = sum of nightly shortfalls
Worked example
Using the starting values in the calculator above:
| Input | Value |
|---|---|
| Sleep you need per night | 8 hours |
| Sleep each night | 7 entries |
| Result | Value |
|---|---|
| Sleep debt this period | 6.5 |
| Average sleep | 7.1 |
| Average shortfall per night | 0.9 |
| Nights under 7 hours | 3 |
How to read the result
Weekend lie-ins recover some short-term debt but do not fully reverse the effects of regular short sleep; consistent sleep times work better.
Persistent tiredness despite enough sleep can signal a sleep disorder worth discussing with a doctor.
General information, not medical advice. Speak to a qualified health professional before making changes to diet, exercise or treatment.
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Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
Most adults need seven to nine hours a night.
Partly, with extra sleep over the following days, but regular adequate sleep is what matters most.
It affects concentration, mood, metabolism and long-term health.
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