Time duration adder
Add up a list of durations or net them against each other. Each row takes hours, minutes and seconds, with an add or subtract toggle, and the tool sums them into a single total.
The result is shown as HH:MM:SS along with the total seconds and decimal hours, which is handy for billing, audio editing, training logs and project time.
It is privacy-first: every duration you enter stays in your browser and is never sent anywhere.