This time calculator adds or subtracts two durations given in hours, minutes and seconds. Each is converted to total seconds, combined, and turned back into H:MM:SS with carrying handled — so 2:45:00 + 1:30:00 = 4:15:00. It also reports the answer in total minutes and total seconds.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: seconds arithmetic, recomputed in code.
How it works
Working in seconds removes the awkwardness of carrying. Add the two second-totals (or subtract for the difference), then peel off whole hours (÷ 3600), whole minutes from the remainder (÷ 60), and the leftover seconds. That's why values above 59 in any field still come out correct.
Worked examples
Adding 2:45:00 and 1:30:00:
Subtracting 1:45:00 from 5:00:00:
Adding with seconds carry, 1:20:30 + 0:50:45:
So the totals are 4:15:00, 3:15:00 and 2:11:15 — the last one carrying 75 seconds into an extra minute.
Frequently Asked Questions
To seconds, add, back to H:MM:SS. 2:45:00 + 1:30:00 = 15300 s = 4:15:00.
Choose subtract. 5:00:00 − 1:45:00 = 3:15:00. Second larger → negative result.
Yes. Summed in seconds, so 90 s → 1:30 and 75 min → 1:15 automatically.
No — this adds lengths of time. For a new time of day, use an add-time calculator.
Lap times, task durations, clip lengths, remaining time — anything additive.