Chronology Lab

Date difference calculator

Measure spans between any two instants and copy the results into project plans or reports.

Precision span

Interactions

Span calculator

The tool uses local device time, so it stays aligned with your clock whether you are drafting a kickoff timeline or logging an explorer’s itinerary.

Choose both instants to see the length.

How it works

Details

The calculator reads the local timezone from your browser and treats the inputs as ISO timestamps. The displayed span always reports the absolute difference, and the heading clarifies whether the second instant is later or earlier.

  • Supports time-of-day so you can measure schedules down to the minute and second.
  • Handles past dates just as comfortably, revealing how long ago an earlier event took place.
  • Renders the output using compact units so teams can share the span alongside progress reports.
Tip: Use UTC timestamps for consistent reporting across continents, and record the result in documents with a brief note about the timezone implied by your device.