Sleep Debt Clock

What is "sleep debt"?

Think of sleep like a bank account. When you regularly get less sleep than you need, you build up “sleep debt,” and when you give yourself extra time to sleep, you can gradually recover. Research supports the idea that accumulated sleep loss matters and that recovery sleep can help restore alertness and performance—making sleep debt a useful, simple way to keep an eye on your sleep habits.

One short night is easy to shrug off. A week of them adds up. Sleep Debt Clock reads the sleep already in Apple Health and keeps a running balance: every night under your goal adds to your debt, and every night over it pays some back.

YOUR BALANCE AT A GLANCE
• A debt ring shows where you stand: Well rested, Manageable, Elevated or High
• Last night's sleep compared with your goal
• Your last 7 nights, with your average and how often you met your goal

EVERY NIGHT, IN DETAIL
• Scroll through each night's surplus or shortfall
• Tap any night to see how long you slept and how it changed your balance

WATCH THE TREND
• See your debt rise and fall over 30 days, 90 days or all time
• Drag across the chart to check any day

MISSING NIGHTS, HANDLED
Forgot your watch? For recent nights with no sleep data, Sleep Debt Clock asks you for an estimate instead of silently counting zero. Older gaps are filled with your recent average. Estimates stay in the app, are clearly marked, and are replaced automatically if real data shows up in Health.

NEW TO SLEEP TRACKING?
Tap "Try with Sample Data" to explore the app with example nights while you wait for your own.

MAKE IT YOURS
• Set your nightly sleep goal
• Choose the date tracking starts
• Carry over debt you already had when you start

PRIVATE BY DESIGN
Sleep Debt Clock only reads sleep data. It never writes to Apple Health. There are no accounts, ads, analytics or servers. Your data stays on your iPhone.

WHAT YOU NEED
Sleep data in Apple Health that includes Time Asleep. That comes from an Apple Watch worn to bed, or from any sleep-tracking app that saves sleep stages to Health. An iPhone's bedtime schedule on its own records only Time in Bed, which isn't counted.

Sleep Debt Clock is for general wellness and information only. It is not a medical device and doesn't diagnose or treat any condition. If you have concerns about your sleep, talk to a healthcare professional.