How to Calculate the Number of Days Between Two Dates

Counting days between dates comes up constantly — deadlines, event planning, notice periods and age. Here's how to do it accurately.

The tricky parts

Doing it by hand is error-prone because months have different lengths and leap years add a day. That's why a calculator is safer for anything important.

Common date questions

• How many days until an event? Count from today to the date.
• How old am I exactly? Years, months and days from your birth date.
• What date is 90 days from now? Add days to a start date.

Free date tools

Use the Date Difference Calculator for the gap between two dates, the Days Until Date counter for events, the Add/Subtract Days tool to find future or past dates, and the Age Calculator for your exact age.