Add Days to Date

The add days to date calculator moves a date forward by a chosen amount. Pick a start date, enter a number, choose whether to add days, weeks, months, or years, and it returns the resulting date along with the day of the week it lands on.

This answers a question that comes up all the time: what will the date be a certain number of days from now? Delivery estimates, warranty periods, project deadlines, appointment follow-ups, and notice periods are all expressed as "so many days from" a starting point. Rather than counting squares on a calendar and risking an error around month ends, you get the exact target date instantly.

Adding days, weeks, months, and years each behaves the way you would expect. Days and weeks simply move forward by the right number of days. Months and years step by calendar month, clamping at the end of the month where necessary — so adding one month to 31 January gives the last day of February, not an invalid 31 February. Leap years are handled automatically.

To use it, choose your start date, type an amount, pick the unit, and press Calculate date. The result appears instantly below, with its weekday, and everything is computed privately in your browser.

If you need to go backwards instead, the subtract days from date calculator works the same way in reverse, and the days between dates calculator counts the gap between two dates you already know.

The chosen amount is added to the start date. Days and weeks add a fixed number of days; months and years step by calendar month and clamp to the end of the month, so 31 January plus one month is the last day of February. The weekday of the result is read from the calendar.