Sleep Cycle Calculator
Stop waking up tired. Our calculator uses 90-minute sleep cycle intervals to help you time your alarm so you wake up at the light end of a sleep cycle.
Sleep Refined
Wake up feeling refreshed by aligning your alarm with natural 90-minute sleep cycles.
The 90-Minute Rule
A typical night's sleep consists of 5 to 6 cycles of approximately 90 minutes each. If you wake up in the middle of a deep sleep cycle, you'll feel groggy and "hungover"—this is called **sleep inertia**.
By timing your alarm to coincide with the end of a cycle, you ensure your body is in the lightest stage of sleep, making it much easier to get out of bed.
Sleep Hygiene Tips
- Avoid blue light (phones) 1 hour before bed.
- Keep your bedroom temperature around 18°C (65°F).
- Limit caffeine intake after 2:00 PM.
- Stick to a consistent sleep schedule, even on weekends.
Stage 1-2
Light sleep where you can be easily awakened. Heart rate starts to slow.
Stage 3-4
Deep sleep (Slow Wave). Critical for physical recovery and hormone regulation.
REM
Rapid Eye Movement. Where dreaming occurs. Vital for memory consolidation.