AbacusKitCalculators & tools
AbacusKit · https://abacuskit.com/global/days-between-dates/ · 2026-10-22

Days Between Dates Calculator

From 1 January to 31 December 2026 there are 364 days. Pick any two dates; tick the box to count the last day too.

Tick this to count both the first and the last day (one more day)

—

Was this helpful?Report an issue

How it works

Enter a start date and an end date. The calculator counts the whole days between them and shows the same period as full weeks and leftover days, as years, months and days, and as hours.

By default the start date is day 0 and the end date is not counted, which is how most people count “days until”. Tick the box to count both end days instead.

Formula and worked example

Days = end date − start date (plus one if the end date is counted). Years and months are whole calendar months from the earlier date; the days left over are counted after that.

For 1 January to 31 December 2026:

  1. Days: 364
  2. Counting 31 December as well: 365
  3. In years: 1 (a full calendar year)

Frequently asked questions

Is the end date counted?

Not by default. From 1 January to 2 January is one day. Tick "Count the end date as well" if you want both the first and the last day included, which makes it two.

How are leap years handled?

The calculator uses the Gregorian calendar. A year is a leap year when it divides by 4, except years that divide by 100 but not by 400. So 2028 has 29 February, and 2100 does not.

How do you count months when they have different lengths?

Months are counted from the earlier date. If the later month is shorter, the day moves to its last day, so 31 January plus one month is 28 February and counts as exactly one month.

What if my end date is before the start date?

The two dates are swapped and the same period is shown. A note under the result tells you.

Can I count only working days?

Use the working days calculator for that. It leaves out weekends and the public holidays of a German state, the UK nations or the US.

Which years work?

Any date from 1900 to 2100.

Sources and methodology

Last updated 2026-10-20. Calculator version 1.0.0.Read how we calculate for our verification process.

Results are estimates for information only and are not financial, tax or legal advice.