About the Time Calculator
Add or subtract time durations with days, hours, minutes and seconds, or add a duration to a specific date and time to find the end time.
How to use it
- Choose “Duration maths” or “Add to a date/time”.
- Enter the values.
- Choose add or subtract.
Formula & method
Total seconds = d×86400 + h×3600 + m×60 + sFrequently asked questions
How do I add hours and minutes?
Convert both to minutes, add them and convert back. This calculator does it automatically, carrying over into hours and days.
Results are estimates for general information only and are not financial, tax, legal or medical advice. Please confirm important decisions with a qualified professional.