How it is calculated
- Days = end date − start date (plus 1 if the end date is counted too)
- Weeks and leftover days: days ÷ 7
- Months: whole calendar months are counted first, then the remaining days
If the end date is before the start date, the result is shown as negative. Months and leftover days are worked out without adding a day for the end date.
Worked example
1 January 2026 to 31 December 2026:
- 364 days (365 days if the end date is counted too)
- 364 days is 52 weeks + 0 days
- In calendar terms: 11 months + 30 days
Reversed, from 31 December 2026 to 1 January 2026, the result is −364 days.
Why your number may differ
This calculator counts calendar days, not working days. For working days, use the working days calculator. Whether to count the end date depends on your need, since some periods count both the first and the last day.