Overview
Plan a task or meeting from either its start or end. Enter the known time and duration to get the other end, with the full date and an overnight warning.
Formula
Convert the time to minutes, add or subtract the duration depending on what you know, then convert back to hours and minutes while adjusting the date.
How it works
Choose what you know
The start time or the end time.
Enter time and duration
Set the date, hours and minutes.
Read the other side
The time and date appear with a midnight warning.
Worked examples
A task starting at 9:00
A 1-hour 30-minute duration ends at 10:30.
A midnight deadline
If the end is 00:30 and the duration is two hours, the task starts at 22:30 the previous day.
Frequently asked questions
Can a task span more than a day?
Yes, up to 72 hours, and the number of extra days is shown.
Are breaks deducted?
No, the duration is full time. Use the work duration calculator for breaks.
Does it depend on the time zone?
Yes, the time is interpreted in your local device zone.
This calculator is for educational and informational purposes only and is not a substitute for professional advice.