About this tool

This calculator handles calendar arithmetic correctly — adding a month to January 31 lands on the last valid day of February rather than overflowing into March, and leap years are accounted for automatically. Combine years, months, weeks, and days in a single calculation to land on exactly the date you need.

Common uses

• Finding a due date a set number of weeks from today
• Calculating contract, warranty, or lease end dates
• Working out a date a certain number of years or months in the past