Time Calculator – Time Difference, Add/Subtract Time, and More
This Time Calculator helps you quickly work with hours, minutes, and seconds. You can calculate time differences, add or subtract time from a starting point, convert between H:M:S and decimal hours, and sum multiple time values.
Time Difference Between Two Times
In the Time Difference tab, enter a start time and an end time in 24-hour format (HH:MM or HH:MM:SS). The calculator returns:
- Duration as H:M:S
- Total hours as a decimal
- Total minutes
- Total seconds
If the end time is earlier than the start time, you can choose to treat it as next day (overnight shift, night work, or events that pass midnight).
Add or Subtract Time
Use the Add/Subtract Time tab to shift a base time by a custom duration. You can enter hours, minutes, and seconds, then select whether to add or subtract this duration from the base time.
The calculator shows:
- Resulting time in 24-hour format
- Resulting time in 12-hour format with AM/PM
- Total shift duration as H:M:S and hours
H:M:S Converter
In the H:M:S Converter tab, enter any combination of hours, minutes, and seconds. The calculator converts this to:
- A standard H:M:S format
- Total hours as a decimal value
- Total minutes
- Total seconds
This is useful for converting timesheet entries or video lengths into a format required by other tools.
Decimal Hours and Time Sums
The Decimal Hours & Sum tab is ideal for timesheets and billed hours. You can:
- Convert a single decimal hours value (such as 7.75) into H:M.
- Paste multiple decimal hour values separated by commas or new lines.
- Get a total in decimal hours, H:M, and H:M:S formats.
This makes it fast to add up work days, project hours, study sessions, or any repeated activity measured in hours.
Why Use a Time Calculator?
Doing time math in your head can be error-prone, especially when converting between hours, minutes, seconds, and decimal formats. A dedicated time calculator helps you:
- Avoid calculation mistakes in schedules and timesheets.
- Convert formats instantly based on your needs.
- Save time when planning work, events, and travel.
Explore More Free Tools
MyTimeCalculator offers many other free tools for time, math, finance, health, and everyday calculations. Try more calculators to speed up your planning and reduce manual work.