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Sleep Worksheet

Estimate sleep duration and 90-minute cycles from bedtime and wake time you enter. Compare to your own target hours. Educational only—not medical advice.

Overnight-safe duration
90-minute cycles
vs your target

Educational sleep worksheet: duration = wake − bed (overnight-safe); cycles = minutes ÷ 90; vs target hours you enter.

Limitation: Educational worksheet only—not a diagnosis or sleep-medicine advice.

Jump to calculator · Sources & review

Free Calculators HubSleep Calculator

How to Use the Sleep Worksheet

Enter assumptions you control; nothing is fetched live.

1

Enter bedtime hour and minute (24-hour clock).

Target hours are yours

Use a clinician- or guideline-informed target for your age and situation—do not treat cycle counts as a prescription.

What It Calculates

Computes elapsed sleep from bedtime to wake (crossing midnight when needed), divides by 90 minutes for an educational cycle count, and subtracts your target hours.

Examples

Classic 23:00 → 07:00

Inputs

bedHour:23
bedMinute:0
wakeHour:7
wakeMinute:0
targetHours:8

Result

8.00 hours (≈5.33 cycles)

480 minutes overnight; 480 ÷ 90 ≈ 5.33; vs target 0.

Short afternoon window

Inputs

bedHour:13
bedMinute:0
wakeHour:14
wakeMinute:30
targetHours:8

Result

1.50 hours

90 minutes same-day; 1 cycle; −6.5 vs an 8-hour target.

Frequently Asked Questions

No. It only arithmetic-checks clocks you enter.

Still have questions about this calculation?

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Formula

durationMinutes = wakeClock − bedClock (add 24h if wake ≤ bed); durationHours = minutes ÷ 60; cycles = minutes ÷ 90.

Formula

wake − bed ​(​​+​24h if needed​)​

Duration

wake − bed ​(​​+​24h if needed​)​

Cycles

durationMinutes ​÷​ 90

Scientific Background

Assumptions: continuous sleep between clocks; no latency or awakenings. Limitations: not polysomnography. Educational only.

Sources & review

Sleep Calculator documents the references behind its formulas and assumptions. Always treat results as educational estimates, not personalized professional advice.

Last reviewed

July 22, 2026

See our methodology and corrections policy.