# Calculate the number of days between two dates

 Start Date End Date

 Tool for calculating the number of days

Calculator that allows you to calculate the number of days between one date and another.
If you want to know how many days there are between two dates, the duration or the time between 2 dates, our online calculator is here to help.

## Number of days per month

The number of days in a month varies depending on the month and whether the year is a leap year or not.
In 1 month there are 30 or 31 days, with the exception of February which has 28 days, or 29 days for leap year.

There are 12 months in the year: January, February, March, April, May, June, July, August, September, October, November and December.
January: 31 days
February: 28 days (or 29 days in a leap year)
March: 31 days
April: 30 days
May: 31 days
June: 30 days
July: 31 days
August: 31 days
September: 30 days
October: 31 days
November: 30 days
December: 31 days

The Gregorian calendar is the most used in the world. It has its origins in a non-religious calendar invented by Julius Caesar (celebrated Roman general and statesman, the conqueror of Gaul).

## Leap year

A leap year is a year that has 366 days instead of 365 days for a common year. The extra day is February 29. A leap year occurs every four years. Why ? To help synchronize the calendar year with the solar year, or the length of time it takes to complete the Earth's orbit around the sun (which is about 365 days and a quarter of a day). February 29 is a date that usually occurs every four years, and is called the leap day.

It takes approximately 365.25 days for Earth to orbit the Sun (a solar year). We usually round the days in a calendar year to 365. To make up for the missing partial day, we add one day to our calendar approximately every four years.