Days Between Two Dates Calculator

The total days figure shows the exact number of days between the two dates. That number is divided by 7 to give full weeks and remaining days, so you can also read the result as 'X weeks and Y days.'

Both dates are converted into a single number using the Julian Day Number (JDN) method, a standard technique used in calendar calculations. The difference between these two numbers gives the exact number of days between the dates, automatically and correctly accounting for leap years and varying month lengths.

• Both dates are converted from year-month-day into a Julian Day Number (JDN).
• The difference between the two JDN values is taken and used as an absolute (positive) value.
• This difference gives the total number of days.
• The total days are divided by 7 to find the number of full weeks.
• The days left over from that division are shown separately as remaining days.

Between May 15, 1990 and July 18, 2026, there are exactly 13,213 days — that is 1,887 weeks and 4 days.

• Enter today's date as the second date to find how many days remain until an event or birthday, or how many days have passed since one.
• The order in which you enter the dates doesn't affect the result — the tool always shows the absolute (positive) day difference.
• It's recommended to use a year value between 1900 and 2100; the calculation may work outside this range too, but its accuracy has been tested specifically for dates within it.

Calculating the number of days between two dates by hand is error-prone, since months have different lengths (28, 29, 30, or 31 days) and leap years appear at irregular intervals. This tool eliminates that problem using the Julian Day Number (JDN) method, a technique that has been used in calendar calculations for decades.

The JDN method converts each calendar date into a single integer counted from a fixed reference point. The difference between the JDN values of two dates directly gives the exact number of days between them — no separate handling of month lengths or leap year rules is needed.

This method automatically applies leap year rules correctly (years divisible by 4 are leap years, except years divisible by 100 unless they're also divisible by 400). For example, 2000 is a leap year, but 1900 and 2100 are not; the tool correctly accounts for this difference.

The resulting total day count can also be expressed as weeks and remaining days by dividing by 7. This is a practical way to express a duration as 'X weeks and Y days,' especially useful for long-running projects or counting down to an event.

This tool is useful for calculating the days remaining until a birthday, finding the gap between two project deadlines, verifying how long a contract or subscription period lasted, or simply seeing a clear picture of the time elapsed between any two dates.