How To Use
Type your time given in hh:mm:ss or decimal format into edit box
Use +/- button (or keybord +/- keys) to add next data field.
Accuracy - number of significant decimal digits is
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Time Calculator
+ x

+ - reset

Time formats - Examples
hh:mm:ss.mshh hours, mm minutes, ss seconds, ms milliseconds
10:30:28.1210 hours, 30 minutes, 28 seconds, 120 milliseconds
72.5:1172 and half hour + 11 minutes = 72 hours and 41 minutes
:11:711 minutes and 7 seconds
:8888 minutes (one hour and 28 minutes)
::2828 seconds
Buttons And Keys
  • Button + : adds next data field preceding by sign '+'
  • Button - : adds next data field preceding by sign '-'
  • Reset : clears all data fields (resets to initial state)
  • red x : deletes data field
  • Keyboard shortcuts : '+' works like 'button +', '-' works like 'button -', 'Enter' works like 'button +'
  • Sign (+/-) Click on the sign left to the data field to change the sign '+/-'
Hour:minute:second calculator
  • Adding Time Calculator - this online tool can add time given in time format as well as decimal time format. The sum appears in result window in hh:mm:ss and decimal time format.
  • Time Format Converter - To convert hour:minute:second time format, type the value into 'edit box'. Decimal format (in hours, minutes or seconds) will appear on the right side of the result window. To translate decimal time format (e.g 10.5 hours) just type the value into data field. The result will appear in the result window (10:30:00)
  • Minutes to hours, seconds to hours, ... conversion - Typing number of minutes e.g. :200 or seconds e.g. ::1000, you can get number of hours, minutes and seconds (3 hours and 20 minutes; 16 minutes and 40 seconds respectively)
  • Adding Time Intervals - If you have a list of time intervals (from hour HH:MM to hour hh:mm) you can easily sum this intervals preceding 'an hour FROM' by sign '-' and 'hour TO' by sign '+'.

All our online converters are free to use. We try to keep our software free of bugs and errors but we do not take any responsibility for any problems caused through the use of these calculators and converters.