Date Calculator
Add or subtract years, months and days from any date and see the resulting date with the day of the week.
Formula
Years and months are applied first, then days. If the target month is shorter than the start day, the date moves to the last day of that month (January 31 + 1 month = February 28, or 29 in a leap year).
Example: March 31, 2026 − 1 month = February 28, 2026. January 15, 2026 + 1 year, 2 months and 3 days = March 18, 2027.
Frequently asked questions
How does it add months when the day does not exist?
The date lands on the last day of the target month. January 31 plus one month is February 28 (February 29 in a leap year).
What is 90 days from today?
Leave the start date as today, set Days to 90 and choose Add.
Does it skip weekends?
No. It counts calendar days. Use the business days calculator to skip weekends and holidays.
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Calendar arithmetic using the Gregorian calendar, for informational purposes.