MathIsimple
Time Calculator

Time Calculator

Add and subtract hours, minutes, and seconds, or find the elapsed time between two clock times — with decimal-hours output for timesheets and payroll.

100% FreePayroll Decimal HoursOvernight Shifts Supported
Add or Subtract Durations
Enter durations as hours, minutes, seconds — switch a row to − to subtract it
Sign
Hours
Minutes
Seconds

How Time Addition Works (and Why Normal Calculators Get It Wrong)

Clock time is base-60: 60 seconds make a minute and 60 minutes make an hour. A standard calculator treats 2.45 as two-and-forty-five-hundredths, not 2 h 45 min — so 2.45 + 1.30 = 3.75 is wrong as clock time. Done correctly: 2 h 45 min + 1 h 30 min → minutes: 45 + 30 = 75 = 1 h 15 min, carry the hour → 4 h 15 min. This calculator carries minutes and seconds automatically, and shows the decimal-hour equivalent (4.25 h) alongside.

Minutes to Decimal Hours Conversion Table

Timesheets and payroll systems use decimal hours. Divide minutes by 60, or read the common values here:

MinutesDecimal hours
5 min0.08 h
10 min0.17 h
15 min0.25 h
20 min0.33 h
30 min0.50 h
40 min0.67 h
45 min0.75 h
50 min0.83 h

Example: a 7 h 40 min shift = 7 + 40/60 = 7.67 decimal hours; at $18/hour that's 7.67 × 18 = $138.06.

Calculating Work Hours Between Two Times

The elapsed-time mode answers the everyday timesheet question: I started at 8:45 AM and left at 5:15 PM with a 45-minute lunch — how many hours is that? Elapsed time is 8 h 30 min; minus the break it's 7 h 45 min = 7.75 payable hours. For shifts that cross midnight (10:00 PM – 6:30 AM), the calculator adds 24 hours automatically instead of returning a negative number, which is the standard convention on time cards.

Frequently Asked Questions

How do I add hours and minutes together?
Add the hours and minutes separately, then carry: every 60 minutes converts to 1 hour. For example 2 h 45 min + 1 h 30 min = 3 h 75 min = 4 h 15 min. The most common mistake is typing 2.45 into a normal calculator — clock time is base-60, not base-10.
How do I convert minutes to decimal hours for payroll?
Divide the minutes by 60. So 15 minutes = 0.25 h, 20 minutes ≈ 0.33 h, 30 minutes = 0.50 h, 45 minutes = 0.75 h. A shift of 7 h 40 min is 7.67 decimal hours. Payroll systems multiply decimal hours by the hourly wage, which is why timesheets ask for decimals.
How many hours are between two times?
Convert both times to minutes since midnight and subtract. From 9:00 AM to 5:30 PM: 17×60+30 − 9×60 = 510 minutes = 8 h 30 min. Subtract unpaid breaks to get payable hours — an 8 h 30 min day with a 30-minute lunch is 8 working hours.
How are overnight shifts calculated?
If the end time is earlier than the start time, the range crosses midnight, so add 24 hours. A 10:00 PM to 6:00 AM shift is 6:00 + 24:00 − 22:00 = 8 hours. The calculator detects this automatically and flags that the range rolls into the next day.
Why does 0.5 hours mean 30 minutes and not 50 minutes?
Decimal hours express a fraction of a full hour: 0.5 × 60 min = 30 min. Reading 7.5 h as "7 hours 50 minutes" is a common timesheet error — it is actually 7 hours 30 minutes.
How do I subtract time from a total?
Switch a row's sign to −. For example +8 h, −0 h 45 min gives 7 h 15 min — useful for deducting breaks, or finding remaining time against a quota like a 40-hour week.
Advertisement