Date Difference Calculator
Enter any two dates and get the difference in days, weeks, months, and years. Also calculates business days excluding weekends.
Why use a Date Difference Calculator?
Calculating the exact number of days, weeks, or months between two dates is surprisingly complex — months have different lengths, years may be leap years, and weekend vs weekday counts matter for project planning. This calculator handles all of that automatically and also shows the breakdown in years, months, and days. Perfect for project deadlines, contract durations, age calculations, and subscription management. See also the epoch converter and timezone converter in the productivity tools category.
Full breakdown
Shows total days, weeks, months, years, hours, weekdays, and weekend days — all calculated from your two selected dates.
Preset ranges
Common ranges like "next 30 days", "past year", or "next year" are available as one-click presets for frequent use cases.
Weekday counting
Counts working weekdays and weekend days separately — invaluable for SLA calculations and sprint planning.
Time unit conversion reference
These conversions are the standard approximations used in calendars, SLAs, and business calculations.
| Unit | In seconds | Approx equivalent | Notes |
|---|---|---|---|
| 1 minute | 60s | — | Exact |
| 1 hour | 3,600s | 60 minutes | Exact |
| 1 day | 86,400s | 24 hours | Exact (ignoring DST transitions) |
| 1 week | 604,800s | 7 days | Exact |
| 1 month | ~2,629,743s | ~30.44 days | Average — actual length is 28-31 days |
| 1 year | ~31,557,600s | 365.25 days | Average including leap years |