Polyphasic Sleep Calculator

1. Pick a schedule. Choose Everyman, Uberman, Dymaxion, biphasic siesta or segmented sleep. Monophasic is included for comparison.
2. Set your start time. Enter when your core sleep begins, or your first nap for nap-only schedules.
3. Read the totals. Check total daily sleep against the 7-hour adult minimum before trying any schedule.

The clock redraws when you change the schedule or start time. Midnight is at the top; blue is core sleep, pink is naps and grey is time awake.

The bar under the list compares your daily total with the 7-hour adult minimum. Green meets it, amber is up to an hour short and red is further below.

Polyphasic sleep means splitting sleep into several short episodes across the 24-hour day instead of one main night of sleep. Most schedules also cut total sleep, sometimes to about 2 hours a day.

Biphasic sleep (a core night plus one nap) and segmented sleep (two night-time blocks) are milder patterns. Everyman, Uberman and Dymaxion are the reduced-sleep schedules people usually mean by polyphasic sleep.

The evidence is not encouraging. A National Sleep Foundation consensus panel screened 40,672 publications, kept 22 relevant papers, and found no evidence supporting benefits from polyphasic schedules. The panel does not recommend schedules that significantly reduce or fragment sleep.

The calculator places the core sleep at your start time, spreads the naps evenly across the time you are awake, and adds everything up.

1. Core block: start time plus core length (Everyman 3: 11:00 PM + 3.5 h = 2:30 AM).
2. Awake window: 24 h minus the core block (20.5 h).
3. Nap spacing: awake window divided by naps + 1 (20.5 h / 4 = about 5 h 8 min).
4. Each nap is centred on that spacing and rounded to 5 minutes.
5. Total: 3.5 h + 3 x 20 min = 4.5 h; shortfall: 2.5 h a day, 17.5 h a week.

For shorter daytime rest without a full schedule change, the nap optimization calculator times a single nap.

The schedule is 2.5 hours short of the 7-hour minimum every day. Over a week that is 17.5 hours, more than two full nights of sleep. Missing any nap, or sleeping through an alarm, pushes the shortfall higher.

Total Sleep

The biggest factor is how much sleep the schedule allows. Anything below 7 hours a day builds a sleep debt.

Body Clock Timing

Naps that fall when your circadian rhythm promotes wakefulness are hard to fall asleep in. Check your natural timing with the circadian rhythm calculator.

Sleep Inertia

Waking from deeper sleep leaves you groggy for a while. The sleep inertia calculator estimates how long.

Sleep Stages

A night normally cycles through light, deep and REM sleep every 80 to 100 minutes, four to six times. Short naps rarely complete a cycle; see the stages of sleep.

Biphasic sleep is the mildest split schedule: one main night plus one daytime nap. It only keeps you out of sleep debt if the two parts add up to at least 7 hours.

Early afternoon is the usual nap slot. Napping late in the day can make it harder to fall asleep at night, which shortens the main sleep and undoes the plan.

• People curious about polyphasic sleep who want to see real clock times and totals before trying anything.
• People with split nights, such as parents or carers, who want to check whether two sleep blocks add up to enough.
• Anyone comparing a siesta routine with a single night of sleep.

Believing The Body Adapts To 2 Hours

The consensus panel found no evidence of benefit, and reduced-sleep schedules are linked to poorer health and performance.

Ignoring The Weekly Total

A small daily gap becomes a large weekly sleep debt. Look at the weekly shortfall, not just the daily figure.

Driving Or Working In Safety Roles While Short Of Sleep

Sleepiness slows reactions. Do not drive or operate machinery when you feel drowsy.

Treating A Nap As A Full Cycle

A 20-minute nap does not replace the deep and REM sleep of a full night.

The clock times and totals are exact for the template you choose; whether a person can actually fall asleep at those times varies a lot.

The evidence says no. A National Sleep Foundation consensus panel found no benefits and linked reduced, fragmented sleep with poorer health, mood and performance.

Uberman gives 6 naps of 20 minutes, about 2 hours a day. That is 5 hours below the 7-hour adult minimum.

Everyman keeps a core sleep of 3.5 to 4.5 hours plus short naps. Uberman has no core sleep, only six 20-minute naps.

Biphasic sleep keeps more total sleep. A 5-hour night plus a 90-minute nap gives 6.5 hours, still 30 minutes short of 7 hours.

One that still adds up to at least 7 hours a day, such as 6 hours at night plus a 60-minute early-afternoon nap. Late-day naps can make night sleep harder.

Segmented sleep splits the night into two blocks with a short awake period between them. Two 3.5-hour blocks give 7 hours in total.

There is no good evidence that people adapt to much less sleep. The consensus panel found no studies supporting the claimed benefits.

This tool spaces naps evenly across your waking hours and rounds to 5 minutes. Other tools may use fixed clock times.

Return to one main night of sleep of at least 7 hours at a regular time, and pay back the debt gradually over several nights.

• National Sleep Foundation consensus panel: Adverse impact of polyphasic sleep patterns (Sleep Health, 2021) (no evidence of benefit; not recommended)
• NHLBI: How much sleep is enough (sleep need by age; sleep debt)
• NHLBI: Sleep phases and stages (cycles every 80 to 100 minutes, four to six per night)
• MedlinePlus: Healthy sleep (adults 7 to 9 hours)
• Sleep Foundation: Napping (best nap time is the post-lunch dip; late naps can disturb night sleep)