index · 24 calculators
All tools
Every calculator and quiz on the site, grouped by what you are trying to do. All free, nothing to sign up for, and each one says which research it rests on.
- Sleep Timing
When to go to bed and when to wake, aimed at 90-minute cycle boundaries so the alarm lands between cycles.
- Nap
The right nap length for your goal, alertness, memory, or recovery, and the latest time to take it.
- Caffeine
The latest safe coffee for your bedtime, and how much of what you already drank is still in your system.
- Alcohol
How tonight's drinks change tonight's sleep, REM loss, wake-ups, and when the last drink should end.
- Wind-down
Screens down and the body's own melatonin window, timed back from your target bedtime.
- Chronotype
A 5-minute quiz that places your body clock, early lark to late owl, and what that means for your schedule.
- Sleep Debt
How much sleep you actually missed over the last 7 nights, whether banking ahead helps, and what the shortfall costs.
- Sleep Need
Your personal baseline, how much sleep your age group actually needs, beyond the generic 8 hours.
- Quality & Hygiene
Score how well you actually sleep, audit the habits that shape it, and set the room temperature right.
Guides
- Alcohol and Sleep: The Science Behind 'I Sleep Better After a Drink'
- How to Recover from Sleep Debt: A Science-Based Plan
- Sleep Needs by Age: NSF Guidelines for Every Life Stage
- What Is Sleep Hygiene? The Habits That Set Up Good Sleep
- Bedroom Temperature and Sleep: Why Cool Wins
- Melatonin for Sleep: What the Research Actually Says
- What Is a Chronotype? Lion, Bear, Wolf & Dolphin Explained
- Delayed Sleep Phase Syndrome: When Night Owl Becomes Clinical
- Social Jet Lag: Why Monday Feels Like a Time Zone Away
- Screens and Sleep: What Blue Light Really Does at Night
- Schedule Fixer
A day-by-day plan to move a drifted, flipped, or shift-work schedule back to where you need it.
- Jet Lag
A multi-day light and sleep plan for crossing time zones, prep days before the flight and recovery days after.
- Family & Shift
Schedules for the people whose nights aren't their own: baby wake windows, teen school weeks, and night-shift day sleep.
Guides
- Teen Sleep Deprivation: Why Your Teenager Is Always Tired
- Jet Lag From New York to London, Paris and Amsterdam
- Jet Lag From Los Angeles to Tokyo, Seoul, Shanghai and Hong Kong
- Jet Lag From New York to Dubai, Doha and Delhi
- Jet Lag Flying From the US West Coast to India (and Back)
- Jet Lag From Los Angeles to Sydney and Auckland
- Shift Work Sleep Guide: How to Sleep Better on Night Shifts
- 4 on 4 off Sleep Schedule: Sleeping on a Rotating 12-Hour Pattern
- Panama Schedule (2-2-3) Sleep Guide
- DuPont Schedule Sleep Guide
- Sleep Banking Guide: How to Prepare for Unavoidable Sleep Loss
- Wake Windows by Age
Looking for the written guides on their own? They are all on the articles page.
Educational information, not medical advice. Consult a healthcare provider for sleep disorders or before taking any supplement.