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Time Duration Calculator: Add and Subtract Hours and Minutes

This free time duration calculator adds or subtracts lengths of time written as hours, minutes and seconds. It shows the total in h:mm:ss and as decimal hours, minutes and seconds.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

Time is counted in sixties, which makes adding it by hand awkward. You meet it when summing film or song lengths, race splits, work hours, cooking steps and call logs.

Type each duration on its own line and choose to add them or subtract them from the first.

How to Use This Tool

  1. Type one duration per line, as h:mm:ss or h:mm.
  2. Choose add or subtract.
  3. Press Calculate.
  4. Copy the answer in the form you need.

How the Calculation Works

Every duration is converted to seconds. The tool adds them, or subtracts the others from the first. The total is converted back to hours, minutes and seconds, and also shown as plain minutes, seconds and decimal hours.

Worked Example

1:45:30 + 0:50:15 + 2:10:00 = 4:45:45. That is 285.75 minutes, 17,145 seconds and 4.7625 decimal hours.

Common Uses

  • Total running time of videos or tracks.
  • Race and lap times.
  • Work and project hours.
  • Adding cooking and prep times.

Tips and Common Mistakes

  • Leave out seconds if you do not need them.
  • A line such as 2 means two hours.
  • Use the time card tool for clock-in and clock-out times.
  • Remember that 1:30 is one and a half hours, not 1.30, so use the decimal hours converter when you need a plain number for payroll.

Next, you may need the time card calculator, decimal hours converter, time zone converter, sleep calculator.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

Add the seconds, minutes and hours separately, carrying any 60 seconds into a minute and 60 minutes into an hour. The tool does this for you.
h:mm:ss, h:mm or just a number of hours such as 2. Minutes and seconds must be below 60.
Yes. If you subtract more than the first value, the result has a minus sign.
The tool shows it for you: total minutes divided by 60, so 1:30 becomes 1.5 hours.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.