Can I add a very large number of days?

Yes — the calculator handles any whole number of days, correctly rolling over months and years as needed.

What if I need to subtract days instead?

Use the Subtract Days from Date Calculator, which works the same way in reverse.

Age, Date & Calendar

Add Days to Date Calculator

Pick a starting date and enter a number of days to add to find the resulting date.

Your calculation is performed in your browser.

Enter a start date and number of days to add.

How it works

The calculator takes your starting date and moves forward by the exact number of days you enter, correctly rolling over month and year boundaries and accounting for leap years.

Formula & methodology

Whole-day calendar arithmetic is used, so month lengths and leap years are handled for you.

ResultResult date = Start date + N days

What each term means

Start date: The date you begin from.
Number of days (N): A whole number of days to add.

Worked example

Adding 90 days to June 1, 2027 gives August 30, 2027.

Common uses

—Finding a return, expiry, or follow-up date a set number of days after today.
—Working out a future deadline by adding a fixed day count to a start date.

Important notes

—Uses the same calendar-accurate engine as the general Date Calculator, focused on the single "add days" use case.