Date Calculator
Add or Subtract Days, Weeks, Months, or Years
From one start date, add or subtract a number of days, weeks, months, or years. The result is shown as a full weekday date. Month and year shifts follow the calendar (e.g. adding one month from 31 January lands on the last day of February).
How to use
Choose Start date, pick Add or Subtract, enter a whole number in Value, and select the unit (days, weeks, months, years). The formatted result updates as you type.
Example
Start 15 March 2026, subtract 6 months, unit months: you land around mid-September 2025. For a 90-day notice, use 90 days with Add instead of guessing months.
Tips
Weeks are exact multiples of seven days. Months and years can shift the day-of-month when the target month is shorter. For only calendar-day addition without units, try Add days.