時間差計算機

時間差計算機の機能

• 01

  Duration between two times

  Pick two dates and times and get the gap broken down into days, hours, and minutes, along with the totals in hours and minutes.

• 02

  Add or subtract time

  Start from any date and time, then add or subtract days, hours, and minutes to land on the exact resulting moment and weekday.

• 03

  Overnight-aware

  When an end time falls earlier than the start on the same day, the calculator treats it as an overnight span and counts the hours correctly.

時間差計算機のよくある質問

How do I calculate the number of hours between two times?

Enter the start and end date and time and the calculator returns the difference as days, hours, and minutes, plus the total number of hours and minutes. It's ideal for working out shift lengths.

How does it handle overnight shifts that cross midnight?

If the end time is earlier than the start time on the same date, the calculator assumes the range runs overnight and adds the extra day so the duration comes out positive and correct.

How do I add hours and minutes to a time?

Switch to add/subtract mode, set a starting date and time, choose add or subtract, and enter days, hours, and minutes. The result shows the new date, time, and day of the week.

Can I calculate duration across different days?

Yes. Both the start and end include a full date, so the calculator correctly spans multiple days, weeks, or longer, not just times within a single day.

Is the time duration calculator private and free?

Yes. It's free with no sign-up and computes everything locally in your browser, so your dates and times are never sent anywhere.