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Sleep calculator

Sleep

Wake time or bedtime in — cycle-friendly suggestions out.

Runs in your browser. Numbers stay on this device — nothing is uploaded to BrowserSpaces for processing.

90-min cycles

Classic cycle length model.

Fall-asleep buffer

Default 15 minutes.

Both directions

Wake → bed or bed → wake.

Use the calculator

6 cycles (~9h)

21:45

5 cycles (~7.5h)

23:15

4 cycles (~6h)

00:45

3 cycles (~4.5h)

02:15

2 cycles (~3h)

03:45

1 cycles (~1.5h)

05:15

Includes ~15 minutes to fall asleep. Guide only.

How it works

How sleep times are suggested

We subtract (or add) N × 90 minutes plus a fall-asleep buffer from your anchor time. Real sleep varies — use as a guide.

Three steps

  1. 1

    Anchor time

    When you must wake or go to bed.

  2. 2

    Direction

    Find bedtime or wake time.

  3. 3

    Pick a cycle

    Usually 5–6 cycles.