How to Use the Date Difference Calculator
- Enter the start date.
- Enter the end date.
- Choose whether to include the end day in the count.
- Read the difference in days, weeks, months and years.
How the difference is calculated
The gap between two dates can be expressed as a total number of days, or broken into years, months and days. Both have to handle months of different lengths and leap years to be accurate.
One thing to decide is whether the count includes or excludes the end date, which can change the total by one. This calculator makes the result clear so you are not left guessing.
Common uses
Date differences come up constantly: counting down to a deadline or event, working out a notice period or contract length, checking how long ago something happened, or measuring the exact duration between milestones.
Because it runs in your browser, you get an instant answer with no sign-up, and the dates you enter are never sent anywhere.
Frequently Asked Questions
Does it account for leap years?
Yes. The calculation uses real calendar dates, so leap years and varying month lengths are handled correctly.
What does 'include end date' do?
Including the end date counts both the first and last day (inclusive), adding one to the total, helpful when counting event days or notice periods.
Can I calculate a difference across many years?
Yes. Any two valid dates work, whether they're days or decades apart.