Add or Subtract Dates

How to use the date calculator

This tool lets you add or subtract any combination of years, months, weeks, and days from a starting date. Select your starting date using the calendar picker, choose whether to add or subtract, enter the number of each time unit you want, and click Calculate. The result shows the exact target date formatted in a readable way.

Common uses for adding and subtracting dates

• Project deadlines: Add 90 days to a project start date to find the target completion date.
• Contract end dates: Add 12 months or 1 year to a signing date to find when a contract expires.
• Countdown planning: Subtract 30 days from an event date to set a reminder deadline.
• Age milestones: Add 18 years to a birth date to find the legal adulthood date.
• Retirement planning: Add years to your current age to project your retirement date.
• Historical research: Subtract years from the current date to find what date was X years ago.

How leap years are handled

The calculator automatically accounts for leap years. If your calculation spans a February 29 (a leap day), the result will be accurate. For example, adding 1 year to February 28, 2024 will return February 28, 2025 (not March 1), because the leap day in 2024 is properly handled. The underlying date library (date-fns) handles all edge cases including month-length variations and leap year rules.

Related tools

• Date Duration Calculator — find the time between two dates.
• Week Number Calculator — find the ISO week number.
• Age Calculator — calculate your exact age.
• Calendar Generator — create and print a yearly calendar.