Date Duration Calculator

Calculate the exact number of days, weeks, and months between two dates.

Working out timelines, notice periods, deadlines, and how long until an event.

How to use it

  1. Pick a start date

    Choose the first date using the date picker.

  2. Pick an end date

    Choose the second date. It must be on or after the start date.

  3. Read the duration

    See the breakdown in years, months and days, plus total days and weeks. Optionally include the end day.

Why use this tool?

Counting the exact time between two dates by hand is tricky because months and years have different lengths and leap years get in the way. This tool gives you the precise number of days, weeks, and months instantly.

Common use cases

Project timelines

Measure how long a project ran or how many days remain until a deadline.

Notice & contracts

Count notice periods, trial periods, or contract lengths exactly.

Countdowns

Work out how many days until a wedding, holiday, or launch.

Frequently asked questions

Does it count leap years correctly?

Yes. The day count uses real calendar dates, so February 29 is handled automatically.

What does “include the end day” do?

It adds one day so both the start and end dates are counted — useful for inclusive ranges.

Is the months figure exact?

The years/months/days breakdown is exact; the standalone “months” total is an approximation based on average month length.

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