Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Circadian Rhythm Adjustment Calculator

Estimate your adjusted bedtime target when shifting your sleep schedule across time zones before or after travel. Helps frequent flyers and shift workers gradually phase-shift their circadian clock to minimize jet lag.

Current Time Zone (UTC offset)

Target Time Zone (UTC offset)

Current Bedtime (h)

Pre-travel Adjustment Days (days)

Light Sensitivity

Fill in the required fields to see your result.

Time Zones

Global Work Shift Overlap Calculator

Calculate how many hours two globally distributed teams actually share during their working days by converting both shifts to UTC and intersecting them. Use it to plan handoffs, standups, or pair-programming windows between offices in different cities.

Team 1 Time Zone

Team 2 Time Zone

Team 1 Work Start (:00)

Team 1 Work End (:00)

Team 2 Work Start (:00)

Team 2 Work End (:00)

Fill in the required fields to see your result.

Key differences

	Circadian Rhythm Adjustment Calculator	Global Work Shift Overlap Calculator
Category	Time Zones	Time Zones
Inputs required	5	6
Result	Recommended Bedtime Adjustment (hours)	Overlapping Work Hours (hours)
What it does	Estimate your adjusted bedtime target when shifting your sleep schedule across time zones before or after travel. Helps frequent flyers and shift workers gradually phase-shift their circadian clock to minimize jet lag.	Calculate how many hours two globally distributed teams actually share during their working days by converting both shifts to UTC and intersecting them. Use it to plan handoffs, standups, or pair-programming windows between offices in different cities.