Nap Calculator

Wake up refreshed, not wrecked. Hit the right sleep cycle every time.

You are falling asleep at

Enter a time above to see your options.

How this works: Sleep runs in roughly 90-minute cycles. Waking at the end of a cycle means you surface from light sleep, feeling alert. Waking mid-cycle pulls you out of deep or REM sleep, producing grogginess. These times are estimates (it takes ~15 minutes to fall asleep on average).

About this tool

Nap Calculator

Wake up refreshed every time. Calculate the perfect nap length or bedtime based on 90-minute sleep cycles. Free online sleep calculator.

Nap Calculator is a free browser-based tool from South Fork Apps. There's nothing to install, no account to create, and no usage limit. Open the page, do the work, and move on.

How it works

Open Nap Calculator in any modern browser on desktop or mobile.
Enter or paste your input into the tool's main field.
Adjust any options shown on the page to match what you need.
Copy or download the result and continue with your work.

Why use a browser tool

Browser tools beat installable apps when the job is small. You don't have to manage updates, sign in, or wait for a heavy program to load. Nap Calculator runs entirely in your browser. Your input never leaves your device, no analytics watch what you type, and the page stops working the moment you close the tab.

Privacy and data

South Fork Apps tools process everything client-side in JavaScript. No server sees your data. Nothing is stored, logged, or sent anywhere. If you're working with sensitive content, you can verify by opening the page once, disconnecting from the internet, and watching Nap Calculator keep working.

More Everyday Tools About South Fork Apps Privacy