Time Calculator
Instantly calculate time differences between two times and add or subtract durations with decimal hour display
Features
Two types of time calculations on one screen
Calculate time differences and add or subtract durations without switching views
Automatic calculation as you type
Results display instantly when you enter times or durations—no submit button needed
Display in hours, minutes, and decimals
View both "8 hours 25 minutes" and "8.42 hours" simultaneously for easy transcription
Copy results with one click
Copy only the decimal numbers to paste into spreadsheet applications
How to Use
Calculate time difference
Enter start and end times in the "Time Difference" section using 24-hour format like "9:15"
Add or subtract durations
Enter hours and minutes in the "Duration Calculation" row, then select + or − for the second and subsequent rows
Add rows for totals
Use "Add row" to add up to 10 rows and total work hours from multiple days
Copy and transcribe results
Use the copy button to copy either "X hours Y minutes" or decimal numbers only, then paste into time tracking sheets or spreadsheets
Use Cases
Calculate daily work hours
Find actual working hours between clock-in and clock-out times, minus breaks, and enter into attendance records
Calculate weekly wages
Add up work hours from multiple days and convert to decimal hours for easy multiplication by hourly rate
Adjust video and audio lengths
Add or subtract durations of different clips to check if the total runtime meets your target
Estimate total schedule duration
Combine travel and work times to determine the total length of your day's schedule
Knowledge Base
Formula for converting minutes to decimal hours
To convert minutes to decimal hours, calculate "minutes ÷ 60". For example, 25 minutes is 25 ÷ 60 = 0.4166…, which rounds to 8.42 hours when 8 hours 25 minutes is expressed in decimal form.
Why work hours are expressed in decimals
Wage calculations require multiplying work hours by hourly rate, which cannot be done with sexagesimal "hours and minutes". Converting 8 hours 25 minutes to 8.42 hours allows you to multiply directly by the hourly rate in a spreadsheet.
- Hours and minutes notation：Used for human-readable attendance records and communications, where minutes are carried over when reaching 60 to show "8 hours 25 minutes".
- Decimal hours notation：Used for calculations, where 1 hour is 1.0 and minutes are divided by 60 to show decimals like "8.42 hours".
Difference between sexagesimal carry-over and unit conversion
Since hours and minutes use base-60, adding 45 minutes and 30 minutes results in 1 hour 15 minutes, not 75 minutes. Converting time to other units like seconds or days is unit conversion, which is handled by the "Time Conversion" tool.
Safety and Privacy
Runs entirely in your browser
Your input data is processed only within your browser and is never sent externally.
Processing only in your browser
Time calculations is processed entirely within your browser, and input data is not sent to any server.
Communications encrypted with HTTPS
Page loading is also encrypted by TLS, and content cannot be read by third parties.
No transmission to third parties
Input content is not sent to external services such as ad networks or trackers.
No automatic saving of results
Input times and durations and input suggestions are not stored on the server.
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Updates
- update #269
Added time calculator that can compute time differences and add/subtract hours together