UTILITIES · FREE TOOL
Duration calculator
Add or subtract durations and convert the result to seconds and decimal hours.
Your inputs
Enter your values, then calculate.
Decimal-point numbers; displayed rounding does not change internal values. Calculations stay on this device.
YOUR RESULT
Make the numbers clear.
Save calculation JSON ↓Calculation breakdown
Scroll sideways to see every column. You can also focus the table and use the arrow keys.
How this calculation works
Duration arithmetic has no date, time zone or daylight-saving convention. H:MM means hours:minutes. Minutes/seconds stay00–59; negative results are allowed for subtraction.
Check the assumptions
Use the stated units and conventions. This tool supports the workflow described here; it does not infer missing information or outside rules.