Sleep & Mattress Calculators
Free, practical tools for better rest — time your sleep cycles, track sleep debt and efficiency, size a mattress, find your ideal firmness, and set a caffeine cutoff before bed.
Sleep Cycle Calculator
Find the best time to go to bed or wake up by counting back in ~90-minute sleep cycles, so you wake at the end of a cycle and feel less groggy
Sleep Debt Calculator
Add up the hours you slept this week against your target to see your accumulated sleep debt or surplus and your average nightly sleep
Sleep Efficiency Calculator
Work out the share of time in bed you actually spent asleep from your time in bed, time to fall asleep, and minutes awake during the night
Mattress Size Calculator
Look up standard US mattress dimensions in inches and centimetres, surface area, suggested sleepers, and a comfortable minimum room size
Mattress Firmness Finder
Get a suggested mattress firmness on a 1–10 scale from your sleep position and body weight to anchor your mattress shortlist
Caffeine Cutoff Calculator
Find the latest time to stop drinking coffee before bed, using caffeine's half-life to estimate when the dose decays to a sleep-friendly level