Time Calculator

How to use the Time Calculator

1. Enter the first time – days.
2. Enter the first time – hours.
3. Enter the first time – minutes.
4. Enter the first time – seconds.
5. Choose the operation.
6. Enter the second time – days.
7. Enter the second time – hours.
8. Enter the second time – minutes.
9. Enter the second time – seconds.
10. Press Calculate. The result updates automatically as you type.

About the Time Calculator

Time does not use base 10, so adding 2:45:30 and 1:30:45 on an ordinary calculator gives nonsense. This calculator carries seconds into minutes and minutes into hours for you. It is handy for adding up race splits, video and audio lengths, cooking stages, flight legs or billable work sessions.

You can enter values larger than normal, such as 90 minutes or 200 seconds, and they will be normalized. If the second time is larger when subtracting, the result is shown as a negative duration.

Formula

Convert both durations to seconds, add or subtract, then convert back:

seconds = days × 86,400 + hours × 3,600 + minutes × 60 + seconds
hours = ⌊total ÷ 3,600⌋, minutes = ⌊(total mod 3,600) ÷ 60⌋, seconds = total mod 60

Example calculation

Using the default values:

• First time – days = 0
• First time – hours = 2
• First time – minutes = 45
• First time – seconds = 30
• Operation = Add (+)
• Second time – days = 0
• Second time – hours = 1
• Second time – minutes = 30
• Second time – seconds = 45

the calculator returns:

• Result (h:mm:ss): 4:16:15
• Days, hours, minutes, seconds: 0 d 4 h 16 min 15 s
• Decimal hours: 4.2708 h
• Total minutes: 256.25 min
• Total seconds: 15,375 s

Frequently asked questions

Last updated: 2026-10-12 · Category: Time & Date calculators