How to Use: Date to Date Calculator

Checking Include end date in calculation counts the final day in your result.

If you want to count how many days something lastedfor examplean event that lasted from the 1st to and including the 4th day of the monththis should be checked (result: 4 days.) Otherwisethe last day would not be counted (returning 3 days).

If you want to calculate the age of somethingleave this unchecked (the last/end date is not counted as one additional day).

The Add time fields link takes you to the Time Duration Calculator where you can add hoursminutesand seconds to your calculation.

The Add time zone conversion link takes you to the Time Zone Duration Calculator where you can calculate the duration between a point in time in one time zone and a different point in time in another time zone.

The Count only workdays link takes you to the Business Date Calculator where you can exclude different dayslike weekends and public holidays.

The calculator adds or subtracts the larger time units before the smaller time units. This means that it adds yearsthen monthsthen days. Although the total number of days in January (31) and February (28) are differentboth are counted as 1 month. In some casesthis method can lead to unexpected results.

For examplein a common yearthe time span between January 28 and March 1 is calculated as 1 month and 1 day (January 28 + 1 month = February 28; February 28 + 1 day = March 1).

Howeverthe time span between January 31 and March 1 is also shown as 1 month and 1 day. The calculator first adds 1 month to jump from January to February. But since February only has 28 days in a common yearit lands on February 28 before adding 1 day to arrive at March 1.

This may seem illogical at firstbut the structure of our calendar means that there is no perfect way of calculating dates including months and years.

Yesall our calculators account for leap years.

Nothis calculator does not account for leap seconds.

Nothis calculator does not take DST changes into account.

You can change the order of the DayMonthand Year fields by selecting a different Short Date format in My Units.

To edit your calculationscroll up to the top of the pagemake your changesand calculate again. The Make adjustment and calculate again is a shortcut to the top of the page.

In our calculations the first day of the entered period is always included. Howeverwe do have the option to include the end day. Try selecting the day after if you don't want a day to count.

Checking Include end date in calculation counts the final day in your result.

If you want to count how many days something lastedfor examplean event that lasted from the 1st to and including the 4th day of the monththis should be checked (result: 4 days.) Otherwisethe last day would not be counted (returning 3 days).

If you want to calculate the age of somethingleave this unchecked. See "What can I use the Date Duration Calculator for?" for 2 examples of calculations.

We are a small team with very extensive websites to managesounfortunatelywe do not have the capacity to share detailed information about our algorithms or provide programming help.

This is most likely not an error but due to the fact that the Julian calendar was still in use in the year you entered. This calendar system was eventually replaced by today's Gregorian calendarbut the date this change happened differed from one country to another.

The calculator uses the Julian-Gregorian switch date of the country you select in the settings under My Units.

Here are 2 exampleswith all the fields filled injust click the Calculate duration after following the links.

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

1. Calculating the duration between 2 points in time:
   • Date to Date Calculator: Count daysweeksmonthsand years between 2 dates.
   • Business Days Calculator: Count working days or non-working days between 2 dates.
   • Time Duration Calculator: Count dayshoursminutesand seconds between 2 dates and times of the day.
   • Time Zone Duration Calculator: Count dayshours, minutesand seconds between a point in time in one time zone and another point in time in another time zone.
2. Adding or subtracting days:
   • Date Calculator: Add or subtract daysweeksmonthsand years to or from a date.
   • Business Date Calculator: Add or subtract working days or non-working days.
   • Date and Time Calculator: Add or subtract days, hoursminutesand seconds to or from a date and time of day.

The General FAQ Page answers your questions about timeanddate.comour servicessite-wide settingscustomization optionsadvertising opportunitiesand copyright policies.