Time Duration Calculator
Find the exact time between two dates, in years, months, days, hours, minutes, and seconds.
Duration in other units
Start date
End date
Why this calculator exists
Working out the exact time between two dates is harder than it looks once leap years and uneven month lengths are involved. This calculator does that arithmetic directly, returning the interval in years, months, days, hours, minutes, and seconds, along with common unit conversions such as total days or weeks. It's built for project timelines, milestone tracking, and any case where an approximate answer isn't precise enough.
Where this calculator is useful
Project planning
Track project timelines and calculate exactly how many days, weeks, or months a project will take.
Tracking a child's age
Calculate a baby's precise age in months, days, hours, and minutes for records and milestones.
Anniversaries
Calculate the exact time since a relationship began, or the countdown to an anniversary.
Birthday countdowns
Find out exactly how many days, hours, and minutes remain until a birthday or other event.
Education & research
Calculate time intervals for academic studies, experiments, or research projects.
Event planning
Plan weddings, conferences, and other events by calculating exactly how much time remains to prepare.
Financial planning
Calculate the duration between financial milestones, loan terms, or investment periods.
General reference
Check how long something has been going on, for record-keeping or simple curiosity.
How this calculator works
1. Pick two dates
Choose a start date and an end date. Use Swap to flip them at any time.
- Works for any two dates, past or future.
- Dates are saved in the URL for sharing.
2. Get the exact duration
The calculator returns the precise interval between the two dates in multiple formats.
- Years, months, days, hours, minutes, seconds.
- Converted to total days, weeks, and average months.
- Both dates shown on calendars.
3. Share the result
Share the duration directly, or copy a link with both dates pre-filled.
- Share on social media.
- Send a direct link with the dates included.