Time Calculator — Add, Subtract & Total Hours

Enter Parameters

Adjust sliders or type values directly

Start Time Hour (0-23)

Start Time Minute (0-59)

min

End Time Hour (0-23)

End Time Minute (0-59)

min

Unpaid Break Duration

min

Real-time Calculation Ready

Adjust parameters to see instant results

AI Summary & Key Formula

Time Calculator Quick Reference

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Quick Answer

A time calculator works out how long you worked between a start and end time: convert both to minutes, subtract, deduct any unpaid break, then convert back to hours and minutes and decimal hours. For example, a 9:00 to 17:30 shift with a 45-minute break is 7 hours 45 minutes, or 7.75 decimal hours, while 8:30 to 18:15 with a 30-minute break is 9.25 hours, including 1.25 hours beyond an 8-hour day. Use it for timesheets and payroll; times use a 24-hour clock, and an end time earlier than the start is treated as an overnight shift.

How This Calculation Works

Values calculate dynamically in real-time as you enter figures or adjust sliders.
The equation on the right is exactly what the calculator runs — check any result by hand.

Core Equation

Elapsed Time:
  Start minutes = start hour × 60 + start minute
  End minutes   = end hour × 60 + end minute (+ 1,440 if the shift crosses midnight)
  Net minutes   = End − Start − Break
  Hours = floor(Net / 60) | Minutes = Net mod 60
  Decimal hours = Net / 60
  Overtime = max(0, Decimal hours − 8)

How to Use the Time Calculator

Quick 3-step guide for accurate and fast calculations

STEP 01

Enter your start time hour (0-23)

In the Time Calculator, fill in Start Time Hour (0-23), Start Time Minute (0-59), End Time Hour (0-23), End Time Minute (0-59) and Unpaid Break Duration.

STEP 02

Read your total duration (hours & minutes)

The Time Calculator instantly shows Total Duration (Hours & Minutes), Total Decimal Hours, Total Elapsed Minutes and Overtime (Above 8h), updating as you type.

STEP 03

Compare scenarios

Change Start Time Minute (0-59) to see how it affects Total Duration (Hours & Minutes), then check the formula below to verify the math.

Specific Instructions:

Enter the start time and end time as hours (0–23) and minutes, plus any unpaid break in minutes. The calculator subtracts the break and shows the total duration in hours and minutes, decimal hours, total minutes and any overtime above 8 hours. If the end time is earlier than the start time, it is treated as an overnight shift ending the next day.

Time Calculator Formula

The Time Calculator uses the following formula, calculated in your browser as you change the inputs:

Elapsed Time: Start minutes = start hour × 60 + start minute End minutes = end hour × 60 + end minute (+ 1,440 if the shift crosses midnight) Net minutes = End − Start − Break Hours = floor(Net / 60) | Minutes = Net mod 60 Decimal hours = Net / 60 Overtime = max(0, Decimal hours − 8)

Sources:

Worked Example: Time Calculator

Shift: 09:00 to 17:30 with a 45-minute unpaid break Elapsed = 17:30 − 09:00 = 8h 30m = 510 minutes Net = 510 − 45 = 465 minutes = 7 hrs 45 mins = 7.75 decimal hours Night shift: 22:00 to 06:30 with a 30-minute break Net = (390 + 1,440 − 1,320) − 30 = 480 minutes = 8 hrs 0 mins

Calculations run in your browser — your inputs are never stored on our servers.Formula sources & methodology

Frequently Asked Questions — Time Calculator

How do I add time in hours and minutes?

Convert everything to minutes, add, then convert back. For example, 2 hours 45 minutes plus 1 hour 30 minutes is (2 × 60 + 45) + (1 × 60 + 30) = 165 + 90 = 255 minutes, which is 4 hours 15 minutes (255 ÷ 60 = 4 remainder 15). The same approach works for a whole week: total each day's minutes, sum them and divide by 60. This calculator does the conversion for a single shift automatically.

How do I calculate total work hours for payroll?

For each shift, enter the start time, end time and unpaid break; the calculator returns the paid duration in hours and minutes and as decimal hours. For example, 8:30 to 18:15 with a 30-minute lunch is 9 hours 15 minutes, or 9.25 hours, with 1.25 hours above 8. Repeat for each day and add the decimal hours to get the weekly total, then multiply by the hourly rate to estimate gross pay.

Can I convert hours to decimal format for payroll?

Yes. Divide the minutes by 60 and add the result to the hours: 2 hours 45 minutes = 2 + 45 ÷ 60 = 2.75 hours, and 7 hours 45 minutes = 7.75 hours. Most timesheets and payroll systems use decimal hours because they multiply cleanly by an hourly rate — 7.75 hours at $20 an hour is $155. This calculator shows each result in hours and minutes, decimal hours and total minutes.