Your Chronotype Results
Results appear here after calculation and stay above the form for quick review.
Interpretation
Calculator Inputs
Enter your typical recent pattern. Use the most representative workdays and free days from the last two to four weeks.
Example Data Table
| Profile | Typical Workday Sleep | Typical Free-Day Sleep | Corrected Midpoint | Estimated Type |
|---|---|---|---|---|
| Office routine | 11:00 PM - 6:30 AM | 12:15 AM - 8:30 AM | 4:03 AM | Intermediate |
| Early riser | 9:45 PM - 5:30 AM | 10:15 PM - 6:15 AM | 2:09 AM | Moderate Morning |
| Late creative worker | 12:45 AM - 7:15 AM | 2:00 AM - 10:00 AM | 5:27 AM | Moderate Evening |
Formula Used
This calculator uses an educational hybrid model built from sleep midpoint logic and daily preference indicators. It estimates chronotype from both timing behavior and self-reported alertness patterns.
- Sleep onset = bedtime + sleep latency.
- Sleep duration = wake time - sleep onset, adjusted across midnight.
- Workday midpoint = workday sleep onset + half of workday sleep duration.
- Free-day midpoint = free-day sleep onset + half of free-day sleep duration.
- Average weekly sleep duration = ((5 × workday duration) + (2 × free-day duration)) ÷ 7.
- Corrected free-day midpoint = free-day midpoint - half of oversleep on free days, when no alarm is used.
- Questionnaire score blends morning alertness, evening energy, wake difficulty, peak focus timing, and free-day variation.
- Final chronotype score = 65% corrected sleep timing score + 35% preference score.
How to Use This Calculator
- Enter your usual bedtime and wake time for workdays.
- Enter your usual bedtime and wake time for free days.
- Add average sleep latency in minutes.
- Tell the calculator whether you use an alarm on free days.
- Rate morning alertness, evening energy, and wake-up difficulty.
- Choose when you usually do your best focused work.
- Press the calculate button to show the result summary above the form.
- Review the chart, interpretation, schedule suggestion, and export options.
Frequently Asked Questions
What does this calculator estimate?
It estimates whether your sleep pattern leans morning, intermediate, or evening by combining corrected sleep midpoint, schedule differences, and daily energy preferences.
Is this a medical diagnosis?
No. It is an educational estimate for planning routines, sleep timing, and productivity windows. Persistent sleep problems should be discussed with a qualified clinician.
Why compare workdays and free days?
Free days often reveal your preferred timing, while workdays reflect social obligations. Comparing both helps estimate social jetlag and hidden sleep debt.
What is corrected midpoint of sleep?
It is the midpoint of sleep on free days adjusted for oversleep. The correction helps reduce the effect of catching up on sleep after shorter workweek nights.
Why does the form ask about alertness and evening energy?
Sleep timing alone can miss how you actually feel. Those questions add a practical preference layer, improving the estimate when schedules are constrained.
Can shift workers use it?
Yes, but results may be less reliable when schedules rotate frequently. Use your most common recent pattern and interpret the output as a rough estimate.
What is social jetlag?
Social jetlag is the gap between your sleep timing on workdays and free days. Larger gaps suggest stronger mismatch between obligations and natural preference.
How often should I recalculate?
Recalculate when your routine changes, such as after a new job, school shift, travel period, or a deliberate effort to change sleep timing.