Time difference calculator

Calculate the elapsed time between two dates and times with time zones.

Start

Format: YYYY-MM-DD HH:mm:ss.SSS

Time zone
UTC

Offset: UTC+00:00

End

Format: YYYY-MM-DD HH:mm:ss.SSS

Time zone
UTC

Offset: UTC+00:00

Results

Signed duration0d 01:00:00.000
Absolute duration0d 01:00:00.000
ISO 8601 durationPT1H
Total milliseconds3600000
Total seconds3600
Total minutes60
Total hours1
Total days0.041667

What this tool is for

Use this calculator to measure the exact elapsed time between two local date and time values, even when they belong to different IANA time zones. It helps when you need a reliable answer without manually converting offsets or guessing how daylight saving time affects the comparison.

Common use cases

  • Comparing a start time in one city with an end time in another city.
  • Measuring elapsed time between logs, incidents, flights, or support windows recorded in different time zones.
  • Checking whether two timestamps cross midnight, a weekend, or a daylight saving time change.

How this calculator works

  • Enter the start and end local date and time in YYYY-MM-DD HH:mm:ss.SSS, then choose the time zone for each side.
  • The tool converts both timestamps to UTC internally, then shows the signed duration, absolute duration, ISO 8601 duration, and total milliseconds through days.
  • Use Now to fill the current time quickly, or Swap to reverse the comparison. Offsets can change around daylight saving time transitions.

How to use

Enter the start and end local date-times, select the time zone for each, then review the automatically calculated duration and copy the value you need.