Date Difference Calculator
Find the number of days, working days, and the y/m/d span between two dates.
Calculate the difference between two dates: total days, a years/months/days breakdown, and the number of working days (Monday to Friday) between them. You can also add or subtract a number of days from a date to find the resulting future or past date, along with its day of the week.
Formula & methodology
Whole-day differences are computed in UTC. Working days count Monday to Friday inclusive of both ends.
Worked example
- 2024-01-01 to 2024-12-31 → 365 days
- 2024-01-01 + 90 days → 2024-03-31
Frequently asked questions
Does it include the end date?
The total-days count is exclusive; the working-days count includes both endpoints.
Can it work out a future date from a number of days?
Yes. Switch to 'Add or subtract days', enter a start date and a number of days (use a negative number to go backwards), and it shows the resulting date and weekday.
Privacy
All processing happens locally in your browser. Your data is never uploaded.