How does the bedtime calculator work?

It counts backward (or forward) in 90-minute sleep cycles and adds about 15 minutes to fall asleep, so you aim to wake between cycles rather than in the middle of deep sleep. It's a rule-of-thumb average, not a measurement of your personal sleep.

When should I stop drinking caffeine before bed?

Caffeine has a half-life of roughly 5–6 hours, so a good default is a last cup about 8 hours before bed. People who are sensitive may want 10–12 hours. This is general guidance, not medical advice.

Are these tools a diagnosis?

No. They're educational estimates based on population averages. Only a physician — often with a sleep study — can evaluate your sleep. If you're consistently tired, snoring, or struggling to sleep, talk to a sleep specialist.

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Simple sleep tools, backed by the science of sleep

Two quick tools to help you plan a better night — plus a 2-minute risk screener. No sign-up, no waiting.

These tools run entirely in your browser. Nothing is saved, stored, or sent to us.

Sleep-cycle calculator

Find your ideal bedtime

Sleep runs in ~90-minute cycles. Waking at the end of a cycle — not the middle — helps you feel more rested. Tell us one time and we'll do the math.

I know my wake-up time I know my bedtime

What time do you need to wake up?

Why 90 minutes?

A full sleep cycle — light sleep, deep sleep, then REM — averages about 90 minutes. Most adults need 5–6 cycles (about 7.5–9 hours). Cycle length varies person to person, so treat these as a helpful starting point, not a rule.

Educational estimate based on averages — not medical advice.

Caffeine timing

When should you stop drinking caffeine?

Caffeine lingers longer than most people think — about half is still in your body 5–6 hours later. Enter your bedtime and we'll suggest a last-cup time.

What time do you usually go to bed?

How we calculated this

Caffeine has a half-life of about 5–6 hours, meaning roughly half is cleared every 5–6 hours. A last cup ~8 hours before bed leaves only about a third of it circulating; ~12 hours leaves very little. Sensitivity varies widely — this is a general guide.

General guidance based on average caffeine metabolism — not medical advice.

A quick note: these tools are for general education and planning — they're estimates based on population averages, not a medical diagnosis or advice. If you're consistently exhausted, snore loudly, or struggle to sleep, the best next step is a real evaluation. Book online or call (602) 206-6262.

Sleep well. Be well.

Tools help — a real evaluation answers.

If poor sleep is affecting your days, a visit with a sleep specialist is the next step. Most new patients are seen within the week.

Book an appointment Call (602) 206-6262

Simple sleep tools, backed by the science of sleep

Find your ideal bedtime

When should you stop drinking caffeine?

Get your sleep apnea risk profile

Tools help — a real evaluation answers.