How to Count the Days Between Two Dates
Counting days between two dates is simple in principle and fiddly in practice because months have different lengths.
A reliable manual method
Count the days left in the start month, add the full months in between, then add the days into the end month. Remember February has 29 days in leap years.
Day-of-year shortcut
Within one year, convert both dates to a day-of-year number (January 1 is day 1, December 31 is day 365 or 366) and subtract.
Years, months and days
A total like 9,000 days is accurate but hard to picture. Breaking it into years, months and days gives a more human answer; both are useful, which is why the date difference calculator shows both.
Try it in your language
The same tool is available in 20 languages, including Español, Français, Deutsch, 日本語 and العربية. See all calculators.