OnlineFreeToolBoxHow-to guide
How to Calculate Duration Online Free
How long did something last? How much time passed between two events? How long until a deadline? This guide shows how to calculate the duration between two dates and times — in hours, minutes and seconds, with totals in days — using a free counter that updates live as you change either date. Use the free duration counter below to work out any time gap in seconds.
How to Calculate Duration — step by step
- Enter the start date and time, or press “Set start to now”.
- Enter the end date and time, or press “Set end to now” — “Swap start / end” flips the two.
- Read the result: it updates live as you change either date and time.
- Read the duration in hours, minutes and seconds, and the totals in days, hours, minutes and seconds.
Tips
- Use “Set start to now” and “Set end to now” to measure from the current moment without typing dates.
- If the end is before the start, the result shows zero — press “Swap start / end” to see the positive duration.
- The tool counts the full gap however many days it covers, so it works for durations longer than a day too.
Frequently asked questions
What if the end is before the start?
The result is shown as zero, and you can swap the dates to see the positive duration.
Can I measure a duration longer than a day?
Yes. The tool counts the full gap between the two dates, however many days it covers.
What if the end time is earlier than the start time?
The result is shown as zero for that combination. Swap the two values to see the positive duration.