26 free calculators, backed by real research

Better sleep, calculated.

Free tools that decode your sleep — caffeine timing, chronotype, sleep debt, and more. Built on peer-reviewed science, not vibes.

Browse calculators ↓ What's my chronotype?
100% free No account needed 6 published studies

The calculators

Each one solves a specific sleep question in under 2 minutes. Pick your problem.

Chronotype Quiz

Most popular

Lion, bear, wolf, or dolphin? 15 questions to find your type and a daily schedule that actually fits your energy.

3 min · Roenneberg MCTQ Take the quiz →

Caffeine Cutoff

New

When's the last safe time for coffee? Enter your bedtime and habits, get a specific cutoff time with a decay chart.

30 sec · Drake et al., 2013 Calculate →

Sleep Debt

Science

Log your last week. We'll show your total debt and the cognitive hit — 7 days of 6hrs ≈ legally drunk.

1 min · Van Dongen et al., 2003 Calculate →

Sleep Efficiency

CBT-I

Time in bed vs. time asleep — the metric sleep clinics actually use. See if you're above or below the 85% mark.

30 sec · Clinical benchmark Calculate →

Nap Calculator

New

Should you nap? How long? When? Based on your wake time, energy dip, and the circadian forbidden zone.

30 sec · Dijk & Czeisler, 1994 Calculate →

Jet Lag Planner

Travel

Flying across zones? Get a day-by-day plan — light exposure, melatonin timing, and when to force yourself outside.

1 min · Eastman & Burgess, 2009 Plan my trip →

Melatonin Guide

Most searched

Most people take too much. Get evidence-based dosage and timing recommendations by age and purpose.

30 sec · AASM Guideline Calculate →

Sleep Cycle

Popular

Find the best times to sleep or wake up based on 90-minute cycles. Wake between cycles — not mid-dream.

10 sec · 90-min cycle model Calculate →

Baby Sleep Needs

Parenting

Age-based sleep schedule with nap windows, wake times, and bedtime recommendations. One tool vs. 10 articles.

15 sec · AAP Guidelines Calculate →

Alcohol Impact

Science

See how drinks affect your sleep stages tonight. BAC decay timeline, REM suppression, and when to safely sleep.

30 sec · Ebrahim et al., 2013 Calculate →

Room Temperature

Popular

Your ideal bedroom temperature, personalized for age, bedding, and whether you run hot or cold.

20 sec · NSF Guidelines Calculate →

Circadian Rhythm Map

Science

Map your personal 24-hour body clock. See when your energy peaks, when to focus, exercise, and wind down.

30 sec · Czeisler et al., 1999 Map my rhythm →

Screen Time Cutoff

New

When to stop screens before bed, based on your device, brightness, and blue light filter. Lux-based science.

15 sec · Gooley et al., 2011 Calculate →

Wake Time Optimizer

New

Fell asleep already? Input when, and get the best alarm times aligned to your sleep cycles.

10 sec · Sleep cycle model Calculate →

Shift Work Planner

Niche

Night shifts, rotating shifts — get a personalized sleep, light, meal, and caffeine schedule that actually works.

1 min · Boivin & Boudreau, 2014 Plan my shifts →

Sleep Apnea Risk

Clinical

STOP-Bang screening in 2 minutes. 8 validated questions, auto-BMI calculation, clear next-steps guidance.

2 min · Chung et al., 2008 Screen now →

Insomnia Severity

Clinical

Validated ISI questionnaire — rate 7 dimensions of insomnia over the past 2 weeks. Clinical severity score with CBT-I guidance.

2 min · Morin et al., 2011 Assess now →

Exercise Timing

New

Best time to work out for better sleep? Chronotype-aware scheduler with optimal, acceptable, and avoid windows.

30 sec · Stutz et al., 2019 Calculate →

Pregnancy Sleep

Parenting

Trimester-specific sleep positions, pillow arrangements, and duration recommendations. Safety alerts included.

1 min · Stacey et al., 2011 Get your guide →

Sleep Latency Test

Clinical

How long should it take to fall asleep? Clinical benchmarking — flags both insomnia and sleep deprivation.

30 sec · Carskadon & Dement, 1982 Test now →

Sleep Quality Score

Science

PSQI-based sleep quality assessment — no wearable needed. Get a 0-21 score with component breakdown.

3 min · Buysse et al., 1989 Score my sleep →

Sleep Hygiene Audit

Popular

Interactive 20-item checklist scored across 5 categories. Radar chart, priority improvements, and cross-tool links.

2 min · Irish et al., 2015 Audit now →

Light Exposure Guide

Science

Sunrise-aware light therapy timing. Solar math calculates your windows — no API, works offline.

30 sec · Wright et al., 2013 Calculate →

Baby Sleep Regression

Parenting

Age-based regression predictor with 6 windows mapped on a visual timeline. Survival guides for each stage.

30 sec · Mindell et al., 2006 Predict regressions →

Social Jet Lag

Niche

Roenneberg's formula: compare weekday vs weekend sleep. See how schedule inconsistency affects your health.

30 sec · Roenneberg et al., 2012 Calculate →

How it works

1

Pick your problem

Each calculator tackles one specific sleep question. Start wherever you're curious.

2

Enter a few things

Bedtime, wake time, coffee intake — quick inputs. Most take 30–60 seconds.

3

Get a real answer

Not generic tips. A specific, personalized result backed by the actual study.

Built on published research

Every formula comes from a peer-reviewed paper. Not a wellness blog, not a mattress company's content team. Actual science.

Drake, C. et al. (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before bedtime. J. Clinical Sleep Medicine.
Van Dongen, H. et al. (2003). The cumulative cost of additional wakefulness. Sleep.
Dijk, D. & Czeisler, C. (1994). Paradoxical timing of the circadian rhythm of sleep propensity. Am. J. Physiology.
Roenneberg, T. et al. Munich ChronoType Questionnaire. J. Biological Rhythms.
Eastman, C. & Burgess, H. (2009). How to travel the world without jet lag. Sleep Medicine Clinics.
Gooley, J. et al. (2011). Exposure to room light suppresses melatonin onset. JCEM.
6
peer-reviewed papers behind the tools
0
formulas from "sleep influencers"

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