Date Calculator

Use this free date calculator to add or subtract days, weeks, months, or years from any date.
About Date Calculations

Date calculations help you find future or past dates by adding or subtracting time periods.

Common Uses:

  • Project Planning: Calculate deadlines and milestones
  • Financial: Due dates for payments and investments
  • Personal: Anniversaries, birthdays, and events
  • Legal: Contract expiration and renewal dates

Calculation Notes:

  • Months are calculated based on calendar months (28-31 days)
  • Years account for leap years automatically
  • Weeks are converted to 7-day periods
  • Results adjust for month and year boundaries

Examples:

  • 90 days from today: Useful for trial periods
  • 6 months before a date: Planning ahead for events
  • 1 year + 3 months: Complex date calculations
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How our date calculator works

1

Enter a start date

Type the start date using the date picker. The calculator accepts any date in the past, present, or future.

2

Choose add or subtract

Add days, weeks, months, or years to the start date, or subtract them. We also support business days only, which skips weekends and common US holidays.

3

Read the result

See the target date, the number of days between dates, and the day of the week. The date calculator handles month-length differences and leap years automatically.

Key things to know about our date calculator:

  • Business days: Useful for project deadlines, contract dates, and shipping estimates. Excludes weekends and US federal holidays.
  • Cross-month math: Adding 1 month to Jan 31 gives Feb 28 (or Feb 29 in a leap year). Our calculator follows the standard date arithmetic used by most calendars.
  • Compare with age: For age-related date math, use the age calculator. For day-of-week or date-offset math, use the date calculator.

For related calculations, try our age calculator.