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Duration Calculator

Add or subtract two durations and read the total in seconds, minutes, hours, days, and weeks.

First duration

Operation

Second duration

Total
2 hours, 15 minutes
0.0134
Weeks
0.0938
Days
2.25
Hours
135
Minutes
8,100
Seconds

How to add or subtract time durations

  1. Enter the first duration

    Fill in any of the days, hours, minutes, and seconds fields. Anything left at zero contributes nothing.

  2. Pick the operation

    Choose Add or Subtract. The total recalculates the moment you switch.

  3. Enter the second duration

    Type the second span into the same four fields; the result updates on every keystroke.

  4. Read the total

    The result appears as a sentence plus exact weeks, days, hours, minutes, and seconds. Click Copy breakdown to grab it.

Why use this tool

Add and subtract in one place

Two duration forms and an operation switch cover both directions; changing any field recalculates immediately.

Four input units, five output units

Enter days, hours, minutes, and seconds in any mix and read the total as weeks, days, hours, minutes, and seconds with up to four decimals.

A sentence you can paste

The total is also written out, for example "1 day, 2 hours, 30 minutes", and the copy button grabs exactly that.

Signed results

Subtracting past zero produces a "minus" total rather than an error, so the direction of a difference stays visible.

No signup, no server

The sums run locally as you type; there is nothing to create an account for and nothing uploaded.

About this tool

This duration calculator adds or subtracts two spans of time entered as days, hours, minutes, and seconds. Every change recalculates the total, which is shown two ways: a plain sentence such as "1 day, 2 hours, 15 minutes" and a row of exact values in weeks, days, hours, minutes, and seconds with up to four decimal places. Fields mix freely, so a value like 90 minutes works fine without converting it to hours first, and subtracting a larger span from a smaller one returns a signed result like "minus 30 minutes" rather than an error.

Typical jobs are the small ones: totalling timesheet entries at the end of a week, adding up song or clip lengths to see whether a set fits its slot, combining flight legs and layovers into a real travel time, or taking a lunch break out of a shift. Editors summing footage before a video trim get an exact running length in seconds as well.

The arithmetic runs on your machine as you type; there is no server round-trip and nothing to submit. For the gap between two calendar dates rather than two abstract spans, the date difference calculator counts days, weeks, months, and years, and single-unit conversions such as seconds to hours are also covered by the unit converter.

Frequently asked questions

What can the duration calculator do?
Enter two durations in days, hours, minutes, and seconds, choose whether to add or subtract the second from the first, and the tool shows the combined total expressed in several units at once plus a readable breakdown.
What happens if the result is negative?
If you subtract a larger duration from a smaller one the total is shown as a negative span, for example "minus 30 minutes", so you can still see the size and direction of the difference.
Which units does it convert to?
The total is shown as exact seconds, minutes, hours, days, and weeks, with fractional values where needed, plus a human-readable breakdown such as "1 day, 2 hours, 30 minutes".
Do I have to fill in every field?
No. Leave any field blank or at zero and it simply contributes nothing. You can work purely in minutes, purely in hours, or mix units however you like.
Is anything sent to a server?
No. All arithmetic happens in your browser as you type. Nothing is uploaded, stored, or logged.

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