Date Difference Calculator — Complete Guide
Calculating the number of days between two dates manually is error-prone, especially when months have different lengths or when the period spans a leap year. This tool gives you the exact number of days, weeks, and months between any two dates instantly.
What you can do with Date Difference Calculator
- Calculating how many days until a deadline, event, or date
- Finding how long ago something happened
- Calculating contract durations and notice periods
- Working out age in days or weeks
- Project planning and timeline calculations
How to use Date Difference Calculator
Select or enter the start date
Select or enter the end date
The difference in days, weeks, and months is calculated instantly
Tips for best results
The result includes or excludes the start and end dates depending on whether you are counting inclusive days or the gap between them
Use the Business Days Calculator if you need to exclude weekends
Other tools you might find useful
Frequently asked questions
Does the calculator account for leap years?
Yes. The calculation uses actual calendar dates, so February 29 in leap years is correctly included when it falls within the range.
How do I calculate someone's age in days?
Enter their birthdate as the start date and today as the end date. The result is their age in days.