How are the days between dates calculated?

The number of days is the difference between the start and end date. For example, Jan 1 to Jan 2 = 1 day.

Are the start and end dates included?

The calculator counts the difference — not both endpoints. If you want both included, add 1.

How are months calculated?

Months are calculated using calendar months. For example, March 15 to April 15 = exactly 1 month.

Date Calculator – Days Between Two Dates

Name: Days Between Dates
Author: Miikka

Calculate how many days, weeks, months or years are between two dates. Looking ahead instead? See days from today — e.g. 30, 60 or 90 days from today.

By Miikka · CalcBrew · Updated Oct 14, 2026

Start dateEnd date

Quick picks

The days between dates calculator tells you how many days, weeks, months and years lie between two dates. You can choose whether to count the end dates, which matters for things like rental periods and contract terms.

How the calculator works and what it’s for▾

How the day count works

The calculator measures the span between your chosen dates, automatically accounting for the different lengths of months and for leap years.

The same interval is shown in several units: total days as well as weeks, months and years, so you get the figure that suits your situation.

Counting the end dates

You can decide whether to include both the start and end date, or only the days in between. This changes the result by exactly one day.

The choice is essential for things like rental days, holiday days or due dates, where conventions differ.

What the calculator is used for

Typical uses include working out the length of a project, tracking the days left until an important event and finding an age or the distance to an anniversary.

It also suits the precise counting of contract periods, warranty terms and deadlines.

Good to know

The number of months and years is always approximate, because months vary in length — the most precise unit is always the total number of days.

February 29 in a leap year is handled automatically, so you never have to adjust the figure by hand.

🔄 Reviewed June 2026

Frequently asked questions

Cite this calculator

APACalcBrew. (2026). Days Between Dates. https://calcbrew.com/days-between-dates

MLA“Days Between Dates.” CalcBrew, 2026, calcbrew.com/days-between-dates.

Link to https://calcbrew.com/days-between-dates. Results are estimates; cite the underlying formula or data source for academic work.