😴 Sleep Calculator
Calculate the best times to go to sleep or wake up based on your sleep cycles. Wake up feeling refreshed and energized.
Calculate the best times to go to sleep or wake up based on your sleep cycles. Wake up feeling refreshed and energized.
Each sleep cycle is ~90 minutes. Waking between cycles helps you feel more rested.
Avoid napping after 3 PM as it can interfere with nighttime sleep.
Power Nap (10-20 min): Boosts alertness without grogginess
? Short Nap (30 min): Good for memory and creativity
Full Cycle (90 min): Complete sleep cycle, best recovery
Sleep isn't a uniform state×it occurs in cycles of distinct stages that repeat throughout the night. Understanding these cycles helps you wake up feeling refreshed rather than groggy.
Stages 1 & 2. Easy to wake from. Heart rate slows, muscles relax.
Stage 3. Body repairs, immune system strengthens. Hard to wake.
Dreams occur. Brain processes memories and emotions.
A complete sleep cycle lasts approximately 90 minutes. Waking at the end of a cycle (during light sleep) feels natural, while waking during deep sleep causes grogginess and sleep inertia that can last 30+ minutes.
| Age Group | Recommended Sleep | Sleep Cycles |
|---|---|---|
| Newborn (0-3 months) | 14-17 hours | Variable |
| Infant (4-11 months) | 12-15 hours | 8-10 cycles |
| Toddler (1-2 years) | 11-14 hours | 7-9 cycles |
| Preschool (3-5 years) | 10-13 hours | 7-9 cycles |
| School Age (6-13 years) | 9-11 hours | 6-7 cycles |
| Teenager (14-17 years) | 8-10 hours | 5-7 cycles |
| Adult (18-64 years) | 7-9 hours | 5-6 cycles |
| Older Adult (65+) | 7-8 hours | 5-6 cycles |
Stop using phones, tablets, and computers 1 hour before bed. Blue light suppresses melatonin production.
Ideal bedroom temperature is 60-67×F (15-19×C). Your body needs to cool down to initiate sleep.
Go to bed and wake up at the same time daily, even on weekends. This strengthens your circadian rhythm.
Avoid caffeine at least 6 hours before bed. It has a half-life of 5-6 hours in your system.
Use blackout curtains and remove all light sources. Even small lights can disrupt sleep quality.
Develop a pre-sleep routine: reading, stretching, meditation, or a warm bath 1-2 hours before bed.
The National Sleep Foundation and American Academy of Sleep Medicine recommend these sleep durations based on age. Both getting too little and too much sleep are associated with negative health outcomes:
| Age Group | Recommended Sleep | May be Appropriate | Not Recommended |
|---|---|---|---|
| Newborns (0×3 months) | 14×17 hours | 11×13 or 18×19 hrs | <11 or >19 hrs |
| Infants (4×11 months) | 12×15 hours | 10×11 or 16×18 hrs | <10 or >18 hrs |
| Toddlers (1×2 years) | 11×14 hours | 9×10 or 15×16 hrs | <9 or >16 hrs |
| Preschoolers (3×5 years) | 10×13 hours | 8×9 or 14 hrs | <8 or >14 hrs |
| School-age children (6×13) | 9×11 hours | 7×8 or 12 hrs | <7 or >12 hrs |
| Teenagers (14×17 years) | 8×10 hours | 7 or 11 hrs | <7 or >11 hrs |
| Young adults (18×25) | 7×9 hours | 6 or 10×11 hrs | <6 or >11 hrs |
| Adults (26×64) | 7×9 hours | 6 or 10 hrs | <6 or >10 hrs |
| Older adults (65+) | 7×8 hours | 5×6 or 9 hrs | <5 or >9 hrs |
Sleep cycles run about 90 minutes — waking at the end of one feels more refreshed.
Working back in 90-minute cycles to find ideal bedtimes.
Result: Aim to fall asleep at 9:00 or 10:30 PM (5 or 6 cycles).
Counting cycles forward from an 11 PM bedtime.
Result: Best wake times: 6:00 or 7:30 AM.
Most people need ~15 minutes to drift off.
Result: Set bedtime 15 minutes earlier than the cycle math suggests.
Work back from your wake time in 90-minute cycles, plus ~15 minutes to fall asleep.
Most adults need 7–9 hours; consistency and quality matter as much as quantity.
Often from waking mid-cycle — aim to wake at the end of a 90-minute cycle.