# Sleep Calculator

> Calculate the best bedtimes to wake up feeling refreshed.

Page: https://askcalculators.com/calculator/sleep-calculator/
Definition: https://askcalculators.com/calculator/sleep-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/sleep-calculator/schema.json
Version: 7.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/sleep-calculator/?wakeTime=07%3A00

## Inputs
- wakeTime: I want to wake up at...; type=time; optional; default=07:00

## Outputs
- result: Result; format=text; primary

## Formula
Wake or bed times are generated in 90-minute sleep-cycle intervals plus the entered time to fall asleep.

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.