Circadian Rhythm Calculator Formula

Understand the math behind the circadian rhythm calculator. Each variable explained with a worked example.

Use the Circadian Rhythm Calculator

Formulas Used

Optimal Wake Time

optimal_wake = adjusted_wake

Peak Alertness

peak_alertness = adjusted_wake + 2.5

Afternoon Energy Dip

afternoon_dip = adjusted_wake + 7

Optimal Bedtime

optimal_bedtime = adjusted_wake + 16

Melatonin Onset

melatonin_onset = adjusted_wake + 14

Variables

VariableDescriptionDefault
natural_wakeNatural Wake Time (24h)(hour)7
chronotypeChronotype0
adjusted_wakeDerived value= natural_wake + chronotypecalculated

How It Works

Circadian Rhythm Timing

Your circadian rhythm is an internal 24-hour clock that regulates sleep, alertness, and hormone release.

Key Time Points (Relative to Wake)

| Event | Hours After Wake | |---|---| | Peak alertness | +2.5 hours | | Best coordination | +5 hours | | Afternoon dip | +7 hours | | Melatonin onset | +14 hours | | Optimal bedtime | +16 hours |

Chronotypes

  • Early birds naturally wake 1-2 hours earlier
  • Night owls naturally wake 1-2 hours later
  • Most people are intermediate

    • Worked Example

    An intermediate chronotype who naturally wakes at 7 AM.

    natural_wake = 7chronotype = 0
    1. 01Optimal wake = 7:00 AM
    2. 02Peak alertness = 9:30 AM
    3. 03Afternoon dip = 2:00 PM
    4. 04Melatonin onset = 9:00 PM
    5. 05Optimal bedtime = 11:00 PM

    Ready to run the numbers?

    Open Circadian Rhythm Calculator