Method
Choose an operation and calendar unit, then the calculator moves the starting date by that whole-number amount.
Date & Time / browser tool
Date Calculator
Move through the calendar without tripping over month lengths or leap years.
Your inputs stay on your device
Move a date
live resultMonth and year changes preserve the day where possible, otherwise they use the last valid day of the resulting month.
Useful context
How it works
Use the calculator first, then scan the details below when you want more context about the inputs, result, or assumptions.
How to use it
Enter a starting date, choose add or subtract, enter a whole number, and select the calendar unit.
Understand the result
The result includes the new date, weekday, original date, operation, and amount used.
Example
Adding one month to January 31 uses February 28 in a non-leap year because that is the last valid day of the month.
Notes
Month and year changes clamp month-end dates rather than overflowing into the following month.
Keep moving