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Time Calculator

Add, subtract, and calculate time duration easily.

Add / Subtract Time

3:15
Result

Time Format Converter

3h 15m
Formatted Time
AM

Dr. Alex M., Ph.D.

Technical Specialist | Updated November 2025

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💡 Expert Tips

Decimal Hours for Payroll

Most payroll systems want decimal hours, not hours:minutes. 8:30 (8 hours 30 minutes) = 8.5 decimal hours. Quick conversion: 15min=0.25h, 30min=0.5h, 45min=0.75h. If you worked 7:45, enter 7.75 on your timesheet.

Handling Lunch Breaks

If you worked 9am-5pm (8 hours) but took a 30-minute lunch, subtract the break: 8:00 - 0:30 = 7:30 actual work time. Most employers don't pay for lunch. Always subtract unpaid breaks from total time.

Overtime Calculations

Standard workweek = 40 hours. If you worked 42:30, that's 2:30 overtime. Overtime usually pays 1.5x (time-and-a-half). So 2.5 hours × 1.5 = 3.75 hours of regular pay equivalent.

⚠️ Common Mistakes

Adding Minutes Wrong

Don't just add 45+30=75 minutes. That's 1 hour 15 minutes (1:15), not 75 minutes. When minutes exceed 60, they roll over into hours. This calculator handles that automatically.

Forgetting AM/PM

This calculator uses 24-hour format internally. If calculating work hours, convert first: 8:30am = 8:30, 5:15pm = 17:15. Then subtract: 17:15 - 8:30 = 8:45 worked.

Mixing Formats

Don't add 2.5 hours to 1:30. Convert first. 2.5 hours = 2:30. Then add: 2:30 + 1:30 = 4:00. Stick to one format (either decimal or hours:minutes).

❓ Frequently Asked Questions

How do you add hours and minutes? +

Enter the first time (hours and minutes), click the + button, then enter the second time. The calculator adds them automatically and handles overflow (e.g., 30 min + 45 min = 1h 15min). No mental math needed.

Can you subtract time that results in negative? +

If you try to subtract more time than you have (like 1:00 - 2:00), the calculator will show 0:00 to avoid negative time. In real scheduling, you can't have negative hours.

How do I convert minutes to hours? +

Use the Time Format Converter section. Enter total minutes (like 195) and it automatically shows hours and minutes (3h 15m). Super useful for timesheets.

Does this account for lunch breaks? +

No. This does pure time arithmetic. If you worked 9am-5pm with a 30min lunch, calculate 9am-5pm first (8 hours), then subtract 30 minutes = 7h 30m worked.

What's the difference between hours:minutes and decimal hours? +

2:30 (hours:minutes) equals 2.5 decimal hours. Payroll systems usually want decimal. 15 min = 0.25h, 30 min = 0.5h, 45 min = 0.75h.

📚 References