Guides ·
How to use Time Calculator
Time Calculator. Add and subtract hours, minutes, seconds. Add the minutes; for every 60 minutes carry one hour. 1:50 + 0:20 = 2:10.
The short answer
To add or subtract times, enter durations in hours, minutes and seconds with + or −, or start from a clock time. ClickZM totals them (2:45 + 1:30:30 = 4:15:30) and shows the result as h:mm:ss, decimal hours and total minutes.
It runs in your browser. What you enter is not uploaded.
How to use it
Enter your values in the fields; defaults show a worked example.
Pick the units or options that apply to you.
Read the result, which updates instantly as you type.
Check the formula note under the result to see exactly how it was worked out.
Limits worth knowing
How do I add hours and minutes? Add the minutes; for every 60 minutes carry one hour. 1:50 + 0:20 = 2:10.
What is 7.5 hours in hours and minutes? 7 hours 30 minutes, because 0.5 × 60 = 30.