Super Boring Tools

Search tools

Find a tool by name or what it does.

Date Difference Calculator

Count the days, weeks, months, and years between any two dates, including or excluding the end date.

Options

Calculated live in your browser. Nothing is uploaded.

Pick a start and end date to compare.

How to count the days between two dates

  1. Set the start date

    Both fields prefill with today, so you only need to change the ends of the range you care about.

  2. Set the end date

    Pick the second date. The difference recalculates instantly, even if the end date is before the start.

  3. Toggle include end date

    Turn on Include end date when the final day itself should count, which adds one day to every total.

  4. Read or copy the result

    The breakdown shows years, months, and days plus totals in days and weeks. Click Copy summary to share it.

Why use this tool

Five readouts from one pair of dates

Total days, decimal weeks, a weeks-and-days split, and approximate months and years appear together, alongside the calendar breakdown.

Calendar-accurate breakdown

The years, months, and days figure uses real month lengths, so it stays correct across leap years and 31-day months.

Include-end-date toggle

One switch counts the final day itself, adding a day to the total for billing, leave, and rental style counts.

Either order works

If the end date is earlier than the start date, the tool notes the reversal and reports the gap instead of failing.

Free with nothing to install

No account, no download, and the dates you compare never leave your browser.

About this tool

This calculator counts the days between two dates and expresses the answer several ways at once: whole years, months, and days, plus total days, decimal weeks, a weeks-and-days split, and approximate months and years based on average lengths of 30.4375 and 365.25 days. Both fields start at today, results update on every change, and entering the dates in the wrong order simply reports the size of the gap instead of an error.

The include-end-date toggle settles the classic fencepost argument. From a Monday to a Friday is four days by default, but five if the final day itself counts, which is how billing periods, hotel nights versus rental days, annual-leave requests, and statutory notice periods often work. Other everyday uses include checking how many days remain before a visa expires, measuring the length of a project phase, or working out how long a warranty has left.

The dates are compared entirely in your browser, so nothing you enter is stored or sent anywhere. If the starting point is a birthdate and you want the answer phrased as an age with a birthday countdown, the age calculator is the better fit, and for arithmetic on raw spans of hours, minutes, and seconds rather than calendar dates, use the duration calculator. Day totals convert into other units with the unit converter.

Frequently asked questions

How is the difference between two dates calculated?
The tool counts the whole calendar span from the start date to the end date, then expresses it as years, months, and days, and separately as a total number of days, weeks, and months, so you can use whichever form fits your need.
What does "include end date" do?
Turning it on counts both the start and end dates, which adds one day to the total. This is handy for billing, leave requests, or any case where the final day itself should be counted.
Can the end date be before the start date?
Yes. If you put the later date first, the tool still reports the size of the gap so you always get a sensible answer rather than an error.
Does it account for leap years?
Yes. Calculations use the browser date engine, which knows about leap years and varying month lengths, so a span that crosses 29 February is counted correctly.
Is my data kept private?
Yes. The calculation runs entirely in your browser. The dates you enter are never uploaded, stored, or logged.

Related tools