Time Calculator
Add or subtract two durations in hours, minutes and seconds and get the result as h:mm:ss, decimal hours, total minutes and total seconds — with the carrying shown.
Time Calculator: with the default inputs, result is 4:16:15.
Values over 59 are fine — they carry into hours.
- In words
- 4 hours, 16 minutes, 15 seconds
- Decimal hours
- 4.2708Use this for timesheets and pay calculations.
- Total minutes
- 256.25
- Total seconds
- 15,375
- In days
- —Shown when the result exceeds 24 hours.
Assumptions
- Durations, not clock times; there is no midnight wrap-around.
- Minutes and seconds over 59 are carried into the next unit.
How this is worked out
The formula
total seconds = h × 3600 + m × 60 + s result = seconds₁ ± seconds₂ hours = ⌊result ÷ 3600⌋, minutes = ⌊(result mod 3600) ÷ 60⌋, seconds = result mod 60 decimal hours = result ÷ 3600
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Operation
- Choose one of 2 options.Add (time 1 + time 2) · Subtract (time 1 − time 2)
- Hours
- A number.from 0 to 100000 · whole numbers only · defaults to 2
- Minutes
- Values over 59 are fine — they carry into hours.from 0 to 100000 · whole numbers only · defaults to 45
- Seconds
- A number.from 0 to 100000 · whole numbers only · defaults to 30
- Hours
- A number.from 0 to 100000 · whole numbers only · defaults to 1
- Minutes
- A number.from 0 to 100000 · whole numbers only · defaults to 30
- Seconds
- A number.from 0 to 100000 · whole numbers only · defaults to 45
What you get back
- Resultmain answer
- In words
- Decimal hours
- Use this for timesheets and pay calculations.
- Total minutes
- Total seconds
- In days
- Shown when the result exceeds 24 hours.
What this assumes
- Durations, not clock times; there is no midnight wrap-around.
- Minutes and seconds over 59 are carried into the next unit.
About this calculator
Adding times by hand goes wrong because minutes and seconds carry at 60, not 100. This calculator converts both durations to seconds, adds or subtracts, and converts back — so 2:45:30 plus 1:30:45 is 4:16:15, not 3:75:75.
How to use it
Enter each duration as hours, minutes and seconds. Values over 59 are accepted and carried, so you can type "90 minutes" directly. Choose add to total two durations (two legs of a flight, two work sessions) or subtract to find the difference (how much longer one run took than another). If time 2 is longer than time 1, the result is shown as negative.
Reading the results
- Result is the normalised h:mm:ss.
- Decimal hours is the same duration as a decimal — 4:16:15 is 4.2708 hours. Payroll systems and invoicing tools want this format; 15 minutes is 0.25 h, 20 minutes is 0.3333 h, 45 minutes is 0.75 h.
- Total minutes and total seconds are useful for cooking, exercise intervals and media timestamps.
- In days appears when the total exceeds 24 hours.
Common conversions
| Minutes | Decimal hours |
|---|---|
| 6 | 0.1 |
| 15 | 0.25 |
| 20 | 0.333 |
| 30 | 0.5 |
| 45 | 0.75 |
To convert minutes to decimal hours, divide by 60. To go the other way, multiply the fractional part by 60: 0.42 h × 60 = 25.2 minutes.
Clock times vs. durations
This tool works with durations (amounts of time), not clock times. To find the hours between a start and end time of day — including shifts that run past midnight — use the hours calculator. To count the days between calendar dates, use the date calculator.
Frequently asked questions
▸How do I add hours and minutes?
Add the minutes first; if they reach 60 or more, subtract 60 and carry 1 into the hours. Then add the hours. 2 h 45 m + 1 h 30 m: 45 + 30 = 75 → 15 with 1 carried; 2 + 1 + 1 = 4; answer 4 h 15 m.
▸How do I convert minutes to decimal hours?
Divide by 60. 45 minutes is 45 ÷ 60 = 0.75 hours; 20 minutes is 0.333 hours. Don't write 4 h 45 m as 4.45 — it's 4.75.
▸Why is my result negative?
You subtracted a longer time from a shorter one. Swap the two entries if you just want the size of the difference.
▸Can I add more than two times?
Add the first two, then enter the result as time 1 and the next duration as time 2. For a full week of shifts, the hours calculator multiplies a daily total by days worked.
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