Our story
About SleepDebtCalc
We build the simplest, fastest, most science-grounded sleep tools on the internet — and we make them completely free.
Our mission
Sleep is the single most under-utilized health, performance, and longevity lever available to human beings — and most of the advice on the internet is either fragmented across a hundred articles or locked behind a $99 wearable. We believe everyone should be able to measure their sleep debt, understand their sleep cycles, and design a recovery plan in under 60 seconds, on any device, without signing up for anything.
SleepDebtCalc exists to translate the best of modern sleep science — the work of researchers like Matthew Walker, Andrew Huberman, and the clinical guidelines of the American Academy of Sleep Medicine — into instant, interactive calculators that answer real questions: How much sleep do I owe? What time should I go to bed? Is my caffeine sabotaging my deep sleep?
Always free
All 33 calculators, forever. No paywalls, no signup, no upsell.
No data collection
Your sleep data never leaves your browser. We don't store it.
Evidence-first
Every formula is sourced from peer-reviewed sleep research.
Editorial process
Every article and every calculator on SleepDebtCalc goes through a four-step editorial process before publishing:
- Source review. We start from primary sleep research published in peer-reviewed journals such as Sleep, Sleep Medicine Reviews, and Journal of Clinical Sleep Medicine, supplemented by guidelines from major sleep medicine bodies.
- Algorithm design. Calculator math is built from documented formulas (caffeine half-life pharmacokinetics, 90-minute cycle architecture, sleep efficiency ratios) and stress-tested against published case studies.
- Plain-language writing. Articles are written in everyday language, then reviewed for accuracy and reading level.
- Continuous updates. Posts are revisited at least once per year and updated when new research changes the consensus.
Authors and contributors
Medical-field sleep health writer
Chloe Tyler is a medical-field contributor who writes and reviews practical sleep health guidance with a focus on clarity, safety, and evidence-based recommendations.
Full bio →Tech specialist, writer, SEO strategist, full-stack developer, and AI expert
Adil Sattar is the founder and technical lead of SleepDebtCalc, overseeing its calculator development, technical architecture, search optimization, and content strategy. He builds accurate, fast, evidence-based sleep tools that draw on peer-reviewed research and guidance from organizations including the AASM, CDC, and NIH.
Full bio →What's inside the toolkit
- → Sleep Debt Calculator
- → Sleep Cycle Calculator
- → Wake-Up Time Calculator
- → Bedtime Calculator
- → Sleep Quality Score Calculator
- → Nap Optimizer Calculator
- → Caffeine Cutoff Calculator
- → Screen Time Sleep Impact Calculator
- → Sleep Recovery Planner
- → Weekly Sleep Planner
- → Why Am I Tired Analyzer
- → Sleep Productivity Loss Calculator
- → Life Hours Lost Calculator
- → Jet Lag Recovery Calculator
- → Insomnia Self-Assessment Tool
- → Melatonin Dosage Calculator
- → Sleep Apnea Risk Screener
- → Chronotype Quiz
- → Sleep Myth-Buster Quiz
- → Sleep Hygiene Checklist
- → Sleep Efficiency Calculator
- → Insomnia Severity Index Test
- → Sleep Onset Latency Calculator
- → REM Sleep Calculator
- → Deep Sleep Calculator
- → Circadian Rhythm Calculator
- → Optimal Sleep Window Calculator
- → Sleep Hours by Age Calculator
- → Sleep Age Calculator
- → Sleep Pattern Calculator
- → Biphasic Sleep Calculator
- → Baby Sleep Calculator
- → Baby Nap Calculator
Built on research
Every claim is traceable to a peer-reviewed source or major medical body.
Privacy-first
All calculators run client-side. We never store your sleep inputs.
Built for everyone
Knowledge workers, parents, athletes, students, shift workers, and travelers.
How we stay free
SleepDebtCalc is supported by tasteful, non-intrusive display advertising (including Google AdSense) and the occasional affiliate relationship with sleep-related products we have personally vetted. We never let advertising influence our editorial guidance, and our calculators will always be free, no-signup, and ad-light. See our Privacy Policy and Disclaimer for details.
Get in touch
Questions, corrections, partnership ideas, or research suggestions are always welcome. Visit our contact page or email hello@sleepdebtcalc.com. For terms of use see our Terms & Conditions.
Frequently Asked Questions
Is SleepDebtCalc free to use?+
Yes — all 33 tools are completely free, forever. No signup, no paywall, no subscription. We are funded by non-intrusive display advertising.
Are the tools medically accurate?+
Our tools are based on peer-reviewed sleep science and validated clinical instruments (ISI, PSQI, STOP-BANG). They are screening and educational tools, not diagnostic instruments. Always consult a physician for medical decisions.
Who writes the content on SleepDebtCalc?+
All articles are written and reviewed by our editorial team including Chloe Tyler (medical-field sleep health writer) and Adil Sattar (sleep science researcher and full-stack developer). Sources include NIH, AASM, CDC, and peer-reviewed journals.
How often is the content updated?+
We review and update tool articles quarterly and update clinical thresholds whenever major guideline changes are published by the AASM, ACP, or equivalent bodies.
Can I embed or share these tools?+
You can share links to any tool freely. For embedding or partnership enquiries, please use our contact page.
The information on this site is educational and not a substitute for medical advice. If chronic fatigue persists despite good sleep hygiene, please consult a sleep specialist. Read the full Disclaimer.