About SleepCalcHub
Free, simple sleep calculators that answer one question well and show their working.
Who runs the site
SleepCalcHub is an independent site owned and run by Partha Gupta. Partha builds the calculators and writes the guides.
Partha isn’t a doctor or a sleep specialist, and the pages on this site aren’t clinically reviewed. Everything is based on published guidance from public health organisations and peer-reviewed research, and each page lists the sources it relies on.
What the calculators do
Most of the tools are built around a simple model: sleep runs in cycles of about 90 minutes, and waking at the end of a cycle tends to feel easier than waking in the middle of one. The bedtime, wake-up and nap calculators use that model. Sleep needs by age uses the National Sleep Foundation’s recommended ranges, and the sleep debt calculator compares your recent nights with a target you choose.
These are estimates. Real sleep varies from night to night and from person to person. How bedtime calculators estimate sleep explains the model and its limits in more detail.
How the site is run
- Private by design. Calculations happen in your browser. What you type into a calculator isn’t sent to SleepCalcHub.
- Sources on every page. Claims about sleep link to the organisation or study they come from.
- Plain answers first. Each page leads with the answer, then explains how it was worked out.
- Corrections welcome. If something looks wrong or out of date, please get in touch.