How to use the Date Duration Calculator

This page explains how to use the date duration calculator that calculates the number of days, weeks, months and years between two dates.

Input fields

Date entry

The order of the Day, Month and Year fields depend on your browser's language settings or the order specified in the Site configuration. If the day, month and year are left empty, the current UTC/GMT date is used as default.

List of input fields

Field/Button	Valid range	Comments
Day	1–31	The date of month
Month	1–12	The month as a number or an English month names (e.g. jan or January)
Year	1–3999	The year as a number of as roman numerals (e.g. MCMIX). Please enter four digits (e.g. 1960, not just 60) unless you really want to do calculations between dates around 2000 years ago.
Today	-	Click the button to fill in with today's date

Include end date in calculation

If "Include end date in calculation" is checked, one additional day would be added.

• If you want to calculate the age of something, leave this unchecked (the last/end date is not counted as one additional day).
• If you want to count how many days something lasted, e.g. an event that lasted from the 1st to and including the 4th day in the month, this should be checked (result: 4 days), otherwise the last day would not be counted (returning 3 days).

Examples

Here are two examples, with all fields filled in, just click the "Calculate duration" after following the links.

• How old was Walt Disney when he died?
• Number of days in years 1900-1999

Change from Julian to Gregorian calendar

If the start date is in the Julian calendar and the end date in the Gregorian calendar, this will be adjusted for and reported on the result page.

The old Julian calendar was replaced by the Gregorian calendar which caused a number of days to be lost, depending on when the change happened, the calendar used by the date calculator can be changed in the Country/System setting in the Site configuration.

Linking to the duration calculator

Generally you are allowed to link to the duration calculator from your site, with just a few exceptions as outlined in the Link policy.

Just go to the page that should be linked, and copy the URL/Address from the browser. You can also link to the results page or to a pre-filled form, with default values. To do this, fill in the fields, click "Calculate duration" and then the "Modify the current calculation". That page will contain all values as parameters in the URL so that any other users will see the same values.