About this tool
This calculator adds or subtracts a number of whole days from any starting date using real calendar arithmetic, so leap years and varying month lengths are handled correctly without any manual adjustment. Everything runs in your browser.
How to use the Date Calculator
- Pick a starting date — defaults to today.
- Enter the number of days, or tap a quick preset.
- Choose before or after the starting date.
- Read the resulting date — it updates as you type.
Common use cases
- Finding a deadline that's a set number of days from today (like a 60-day or 90-day notice period)
- Working out a return, refund, or warranty date a fixed number of days after a purchase
- Calculating a due date, follow-up date, or reminder a set number of days out
- Checking what date it was a certain number of days before a known date
Worked example
A 60-day notice period starting today: set the starting date to today, enter 60 in the days field, and leave the direction on "After." The result shows the exact calendar date 60 days out — accounting for whatever mix of 28, 30, and 31-day months fall within that window, which isn't the same as simply adding "2 months" since months vary in length.
Things to watch out for
This calculator counts whole calendar days, not business days — if you need to exclude weekends or holidays from the count (common for legal or contractual deadlines), you'll need to adjust the result manually for those non-counted days. The starting date itself counts as day zero, so "1 day after" a date is the very next calendar day, matching how most people naturally think about counting days forward.
Frequently asked questions
Yes — the calculation uses real calendar date arithmetic, so leap years are handled correctly without any extra steps.
Yes — switch the direction to "before," and the calculator finds the date that many days prior to your starting date.
The starting date counts as day 0 — adding 1 day to a date gives you the very next calendar day, which matches how most people naturally count "days from now."