Enter a starting date and a number of days to add or subtract. The result is the new date. Use a negative number to go back in time. Useful for deadlines, scheduling, and planning.
All date arithmetic uses the browser's native Date object. Day differences are computed by subtracting timestamps and dividing by 86,400,000 ms. Age is broken into complete years, remaining months, and remaining days by comparing each component of the date individually. The page does not call any external library or server during the calculation.
All calculations happen instantly in your browser tab. Our servers are not involved at any point.
For working out an exact age in years, months, and days, try the age calculator. To convert any timestamp into a date, use Unix timestamp. For scheduling work across time zones, see the timezone converter.