Add or subtract dates

Find a date after days, weeks, months or years. Count an Nth day or exclude Saturdays and Sundays.

These results use the example values shown above.

100 days later

2027-01-13

Day of the weekWednesday

The start date is day zero.

Suggest improvements

Business-day mode excludes Saturday and Sunday only. Public holidays and legal deadline rules are not evaluated.

How to use Add or subtract dates

Enter a start date and amount to add. Use a negative amount to move backward.

More options selects weeks, months, years, the Nth day or business days. Months and years clamp missing dates to the target month’s final day. Nth-day counting starts at 1.

Example
October 1, 2026 plus 30 days is October 31, 2026.

Frequently asked questions

Is the start date day zero?

In normal addition, yes. Select Nth-day mode to count it as day one.

What happens on January 31 plus a month?

The date is clamped to the final day of February.

Reviewed: 2026-10-04 · Report an issue