BARO TOOLFREE ONLINE TOOLS

Everyday tool

Sleep Cycle Calculator

Compare simple 90-minute sleep schedules starting from a required wake time or a planned bedtime.

This assumes fixed 90-minute cycles; it does not measure sleep stages or health.

Sleep cycle calculatorEstimate bedtimes or wake times using 90-minute sleep-cycle intervals.
Reference only
A 90-minute cycle is a simplified average. Individual sleep patterns vary.

Try going to bed at

6 cycles21:469h
5 cycles23:167h 30mRecommended range
4 cycles00:466h
This tool does not diagnose sleep disorders. Persistent insomnia, severe daytime sleepiness, loud snoring, or breathing pauses should be discussed with a healthcare professional.

Compare schedules

Is your fixed time bedtime or wake-up?

  • Work backward from wake-up

    Choose I need to wake at and enter the time and sleep latency. Bedtime options are calculated for six, five, and four cycles.

  • Work forward from bedtime

    Choose I will go to bed at and enter when you plan to lie down. Wake times include the delay before sleep plus the selected number of cycles.

  • Read the total duration too

    Six, five, and four cycles represent 9 hours, 7 hours 30 minutes, and 6 hours. Sleep latency is added or subtracted separately.

A worked example

Plan around a 7 a.m. wake-up

Start with
Wake time: 07:00 · time to fall asleep: 15 minutes
Check the result
Six cycles: 21:45 · five: 23:15 · four: 00:45

21:45 and 23:15 fall on the previous evening; 00:45 is on the waking day. The display uses 24-hour times without dates.

Next task

Tools that work well together

Fuel Cost & Mileage Calculator

Estimate fuel costs and an equal per-person share from distance and real-world fuel economy.

→
Random Team Maker

Shuffle a participant list into teams with balanced headcounts.

→
Cooking Unit Converter

Convert recipe amounts in cups or measuring spoons into mL and estimated weight.

→
Random Decision Roulette

Enter low-stakes choices, such as lunch options, and draw one at random.

→