Add or Subtract Days From a Date

Enter a negative number in the days field. For example, -11 moves the date eleven days earlier. The calculator rolls back across month and year boundaries automatically.

Yes. The calculator uses real calendar dates, so February 29 in a leap year is counted. Adding one day to 2024-02-28 returns 2024-02-29, and the year 2026 is not a leap year so its February has 28 days.

This tool adds a number of days to the start date rather than counting a span, so adding 30 days lands exactly 30 days later. If you need the number of days between two dates instead, use a date difference calculator.

Knowing the weekday is often the whole point, such as checking whether a deadline falls on a weekend. The weekday is read directly from the resulting date, so it always matches.

No. Every calculation runs in UTC and treats each date as a plain calendar date with no clock attached, so daylight saving shifts and local time zones never move the result.

No. This calculator counts every calendar day, including Saturdays, Sundays and holidays. If you only want working days, use an add business days calculator instead.

Dates are shown in ISO 8601 form, YYYY-MM-DD, for example 2026-07-11. That format sorts correctly and avoids the day-month ambiguity of numeric-only styles.

Yes. You can enter thousands of days to project far into the future or past, and the calculator still returns an exact calendar date and weekday.

No. The calculation happens entirely in your browser with a pure function, and the dates you enter never leave your device.