What time should I wake up? Use 90-minute sleep cycles plus your age to find optimal times. No signup, no ads.
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🌅 What time should I wake up?
We calculate the best wake-up times that land at the end of a 90-min cycle.
How it works
Your brain runs 90-minute sleep cycles through light sleep, deep sleep, and REM. Waking between cycles feels effortless. Waking mid-cycle — especially in deep sleep — leaves you groggy for up to an hour (sleep inertia).
We also add a 15-minute fall-asleep buffer, the average sleep latency for healthy adults.
Sleep needs by age
| Age | Recommended | Cycles |
|---|---|---|
| Toddlers 1–2 | 11–14 hours | consult pediatrician |
| Children 3–5 | 10–13 hours | 7–8 |
| Children 6–12 | 9–11 hours | 6–7 |
| Teens 13–17 | 9–10.5 hours | 6–7 |
| Adults 18–64 | 7–9 hours | 5–6 |
| Older adults 65+ | ~7.5 hours | 5 |
Source: CDC · American Academy of Sleep Medicine
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Frequently Asked Questions
- How does the calculator determine wake time?
- It counts forward from your bedtime in 90-minute cycles and adds 15 minutes for the average time to fall asleep, then suggests the wake times that land at the end of a cycle.
- What if I wake up tired?
- You probably woke mid-cycle (sleep inertia) or your total sleep was too short. Try moving your alarm 15–30 minutes earlier or later to land on a cycle boundary.
- Can I use this for shift work?
- Yes — enter the time you actually plan to sleep, not a "normal" night. The 90-minute math holds regardless of clock time, though shift workers should also pay extra attention to circadian rhythm and light exposure.
- What is a 90-minute sleep cycle?
- One full pass through light, deep, and REM sleep.
- How many sleep cycles should I get?
- 4–6 cycles (6–9 hours) for most adults.
- How accurate is the 90-minute cycle?
- Individual cycles range from 80–110 minutes. 90 is a strong starting point and works well for most people.
- How long is the perfect power nap?
- 10–20 minutes, per the National Sleep Foundation.
Medical disclaimer. Everything on this page is general educational information and is not a substitute for professional medical advice. Sleep needs vary from person to person. If you have ongoing sleep problems, talk to a licensed healthcare professional.