# SleepCalculator

> Evidence-based sleep timing, bedtime calculation, and sleep cycle estimation platform.

Free, scientifically modeled algorithms based on peer-reviewed circadian science and sleep architecture.

## Calculators & Tools

- [Sleep Calculator](https://sleepcalculator.com/sleep-calculator/): Calculate bedtimes, wake-up times, and optimal sleep cycles.
- [Sleep Cycle Calculator](https://sleepcalculator.com/sleep-cycle-calculator/): Interactive sleep stage timeline visualizer across 90-minute ultradian cycles.
- [Bedtime Calculator](https://sleepcalculator.com/bedtime-calculator/): Calculate exact bedtimes for fixed morning alarm schedules.

## Evidence-Based Guides

- [How Sleep Cycles Work](https://sleepcalculator.com/sleep-guides/sleep-cycles/): Comprehensive guide to NREM and REM ultradian cycles.
- [How Much Sleep Do You Need?](https://sleepcalculator.com/sleep-guides/sleep-duration/): Age-based duration recommendations from AASM and CDC.
- [What Time Should I Go to Bed?](https://sleepcalculator.com/sleep-guides/bedtime-guide/): Timing guidelines to wake up feeling refreshed.
- [What Time Should I Wake Up?](https://sleepcalculator.com/sleep-guides/wake-up-guide/): Circadian alignment strategies for natural morning alertness.
- [The 90-Minute Cycle Truth](https://sleepcalculator.com/sleep-guides/90-minute-cycle/): Scientific reality of ultradian rhythm variations.
- [REM Sleep Explained](https://sleepcalculator.com/sleep-guides/rem-sleep/): Neurobiology and functions of rapid eye movement rest.
- [How to Build a Consistent Sleep Schedule](https://sleepcalculator.com/sleep-guides/sleep-schedule/): Circadian anchoring and weekend schedule drift management.
- [Evidence-Based Sleep Hygiene Rules](https://sleepcalculator.com/sleep-guides/sleep-hygiene/): Environmental and behavioral protocols to optimize sleep efficiency.

## Documentation & Methodology

- [Calculation Methodology](https://sleepcalculator.com/methodology/): Mathematical formulas and assumptions behind our calculators.
- [Scientific Sources & Citations](https://sleepcalculator.com/sources/): Academic bibliography and clinical references.
- [Editorial Policy](https://sleepcalculator.com/editorial-policy/): Rigorous standards for evidence-based sleep wellness content.
- [About Us](https://sleepcalculator.com/about/): Platform mission and principles.
- [Contact](https://sleepcalculator.com/contact/): Editorial team and feedback.