Time Calculator

Add or subtract hours and minutes, or find the duration between two times.

Why Time Math Trips Everyone Up

Time is base-60, not base-10: 7:45 plus 2:30 is 10:15, not 9:75. This calculator handles the carrying for you in two modes: duration between two clock times (with overnight shifts handled automatically) and adding/subtracting time amounts.

Worked Examples

  • Shift from 21:30 to 06:15 → 8 h 45 min (the calculator recognizes the span across midnight).
  • 3 h 50 min + 2 h 25 min → 6 h 15 min.

Decimal Hours for Timesheets

Payroll systems usually want decimal hours: minutes ÷ 60. The calculator shows both formats.

MinutesDecimalMinutesDecimal
15 min0.25 h40 min0.67 h
20 min0.33 h45 min0.75 h
30 min0.50 h50 min0.83 h

8 h 45 min = 8.75 decimal hours — at $20/hour that's $175, computed directly.

Frequently Asked Questions

How does the overnight calculation work?
When the end time is earlier than the start time, the calculator assumes the span crosses midnight and adds 24 hours — right for night shifts up to 24 hours long.
What are decimal hours?
Hours with minutes expressed as fractions: 7 h 30 min = 7.5. Payroll and invoicing systems multiply decimal hours directly by hourly rates.
How do I convert minutes to decimal hours?
Divide by 60. 25 minutes = 25÷60 ≈ 0.42 hours. The calculator shows the decimal value automatically.
Can I add more than 24 hours?
Yes — the add/subtract mode has no upper limit, so summing multi-day totals like weekly work hours works fine.