Does this account for leap years?

Yes. Every date is placed on the real calendar, so February 29 is counted in leap years. For example, January 1, 2024 to January 1, 2025 is 366 days, while the same span a year later is 365.

What if the end date is before the start date?

The calculator swaps them and shows the size of the gap, with a note that the dates were in reverse order.

Should I include the end date?

Include it when both the first and last day count, such as days of a vacation or an event running from the 1st to the 5th (5 days). Leave it out for durations like age or the time until a deadline.

Are time zones a factor?

No. Only calendar dates are compared, so daylight saving changes and time zones don't affect the result.

How many days is 90 days from November 8, 2026?

February 6, 2027. The calculator shows November 8, 2026 to February 6, 2027 as exactly 90 days with the end date not included.

Why is one month sometimes 28 days and sometimes 31?

Months are counted on the calendar, not as a fixed number of days. One month after January 15 is February 15 (31 days later), and one month after February 15 is March 15 (28 days later in a non-leap year).

Free Date Difference Calculator Online

How the difference is counted

By default the start date counts and the end date doesn't, the same way you'd count nights in a hotel: Monday to the next Monday is 7 days. Choose Include end date to count both ends, which adds one day.

Total days = end date − start date (+1 if the end date is included)
Weeks = total days ÷ 7, remainder in days

Years and months are counted in whole calendar months from the start date, then the remaining days. If a month doesn't have the start day (for example the 31st), the last day of that month is used.

Counting days by hand

Here's March 15, 2026 to August 3, 2026, with the end date not included:

Days left in the start month, counting the 15th: March 15–31 is 17 days.
Add the full months in between: April 30 + May 31 + June 30 + July 31 = 122 days.
Add the days in the end month before the end date: August 1 and 2 are 2 days.
Total: 17 + 122 + 2 = 141 days, which is 20 weeks and 1 day.
In calendar terms: March 15 to July 15 is 4 whole months, and July 15 to August 3 is 19 days, so 4 months 19 days.

Ticking Include end date makes it 142 days, or 4 months 20 days. The span covers 100 business days (101 with the end date, a Monday, included).

Example results

End date not included. 2028 is a leap year, so it has one extra day.
From	To	Years, months, days	Total days
Jan 31, 2026	Feb 28, 2026	0 y 0 m 28 d	28
Jan 31, 2026	Mar 1, 2026	0 y 1 m 1 d	29
Nov 8, 2026	Feb 6, 2027	0 y 2 m 29 d	90
Jan 1, 2026	Jan 1, 2027	1 y 0 m 0 d	365
Jan 1, 2028	Jan 1, 2029	1 y 0 m 0 d	366

The second row shows why month counts can surprise you. February 2026 has no 31st, so one month after January 31 lands on February 28, and March 1 is one day later.

Business days

Business days count Monday to Friday over the same span, so the start date counts and the end date only counts when included. Public holidays vary by country and region and are not removed; subtract them yourself if needed.

A full calendar year has 260, 261 or 262 weekdays, depending on which day it starts on and whether it's a leap year. January 1 to December 31, 2026 with the end date included has 261.

Common uses

Deadlines and notice periods: count from today to the due date, end date not included.
Trips and events: include the end date when every day counts, such as a stay from the 1st to the 5th (5 days).
Exact age: enter the date of birth and today's date to get years, months and days.
Countdowns: November 8, 2026 to December 25, 2026 is 47 days, or 6 weeks and 5 days.

Results are estimates for informational purposes and are not financial, medical or professional advice. See our methodology and disclaimer.