Sleep Calculator
Calculate optimal sleep or wake time
:
Time to fall asleep: ~14 min
Sleep Calculator Online - Find Your Optimal Sleep Time
Our free sleep calculator helps you find the best bedtime or wake-up time based on 90-minute sleep cycles. Waking at the right point in your sleep cycle helps you feel rested and energised.
What are sleep cycles?
Stage 1 - Falling asleep
Light sleep, easy to wake. Lasts 5-10 minutes.
Stage 2 - Light sleep
Body temperature drops, heart rate slows. ~20 min.
Stage 3 - Deep sleep
Body recovery, tissue repair. Hardest to wake from.
REM stage
Dreaming, memory processing. ~90 min full cycle.
How much sleep do you need?
| Age group | Recommended sleep |
|---|---|
| Newborns (0-3 months) | 14-17 hours |
| Infants (4-11 months) | 12-15 hours |
| Toddlers (1-2 years) | 11-14 hours |
| Preschool (3-5 years) | 10-13 hours |
| Children (6-13 years) | 9-11 hours |
| Teens (14-17 years) | 8-10 hours |
| Adults (18-64 years) | 7-9 hours |
| Older adults (65+) | 7-8 hours |
Sleep hygiene tips
- Regular schedule - Go to bed and wake at the same time
- Dark bedroom - Use curtains or an eye mask
- No screens - Put your phone away at least 30 min before bed
- Right temperature - Keep the bedroom at 18-20°C
- Avoid caffeine - No coffee at least 6 hours before bed
Frequently asked questions
Why is the sleep cycle 90 minutes?
90 minutes is the average time for one full sleep cycle (through all stages). It can vary from 80 to 120 minutes.
How many sleep cycles do I need?
Adults need 5-6 full cycles (7.5-9 hours). At least 4 cycles (6 hours) to function properly.