Add or Subtract Time Calculator
Add or subtract days, hours, minutes & seconds
What is the Time Calculator?
The Time Calculator is a free online tool that lets you add or subtract two time values expressed in days, hours, minutes, and seconds. Whether you need to find out how long two tasks take combined, calculate the total shift duration across multiple entries, or figure out a remaining time after deducting a break, this tool handles it instantly. Simply enter the two time values, choose Add or Subtract, and get a precise result broken down into days, hours, minutes, and seconds — plus bonus stats showing total hours, total minutes, total seconds, and the equivalent in weeks and days. The calculator works entirely in your browser, requires no login, and gives real-time answers so you can verify your time arithmetic at a glance.
How to Use the Time Calculator
- 1. Enter days, hours, minutes, and seconds for Value A (you can leave unused fields as 0).
- 2. Click the + Add or − Subtract toggle to choose the operation.
- 3. Enter the second time value in the Value B row.
- 4. Click Calculate to see the result instantly in the Result row.
- 5. View the detailed breakdown — total hours, minutes, seconds, and weeks — in the stats panel below.
Formula Used
Result Days = Total Seconds ÷ 86400 (integer)
Result Hours = (Total Seconds mod 86400) ÷ 3600 (integer)
Result Minutes = (Total Seconds mod 3600) ÷ 60 (integer)
Result Seconds = Total Seconds mod 60
Example: 2h 30m + 1h 45m → (9000 + 6300) = 15300 seconds → 0 days, 4 hours, 15 minutes, 0 seconds.
Frequently Asked Questions
How do I add hours and minutes together?
Enter hours and minutes for each value, select Add, and click Calculate. The tool converts everything to seconds, adds, then converts back to a clean hours-minutes-seconds result.
How do I subtract time?
Click the Subtract toggle, enter the larger time in Value A and the smaller in Value B, then hit Calculate. The result is the difference between the two times.
What is 2h 30m + 1h 45m?
2 hours 30 minutes + 1 hour 45 minutes = 4 hours 15 minutes. The 75 minutes becomes 1 hour 15 minutes, so the hour total is 2 + 1 + 1 = 4.
How do I convert a time result to decimal hours?
Divide total minutes by 60 and add to the hours. For 4h 15m: 4 + 15/60 = 4.25 decimal hours. The Total Hours stat in the breakdown panel gives you this directly.