Date Calculator
Add or subtract days, weeks, months or years from a date to find the exact future or past date.
Runs in your browser — your data never leaves your device.
About the Date Calculator
What date is 90 days from today? When does a 3-month notice period end? When does a 1-year warranty expire? Pick a start date, choose add or subtract, and enter any combination of years, months, weeks and days.
The result shows the full date with the day of the week.
How to use the Date Calculator
- Choose the start date (today is filled in).
- Choose Add or Subtract.
- Enter years, months, weeks and/or days.
- Click Calculate date.
Formula
Years and months are added first, then weeks and days.
If the result month is shorter than the start day — for example 31 January + 1 month — the date moves to the last day of that month (28 or 29 February). Leap years are handled automatically.
Examples
- 15 January 2026 + 90 days = 15 April 2026 (Wednesday).
- 31 January 2026 + 1 month = 28 February 2026.
- 1 March 2026 − 2 weeks = 15 February 2026.
Frequently asked questions
How do I count days between two dates instead?
Use our Date Difference Calculator — it shows the years, months, days and total days between any two dates.
Is the start day counted?
No. Adding 1 day to Monday gives Tuesday. If your rule counts the first day too, subtract one day from the result.