Enter the start date above — pick it from the calendar or type it (e.g. 2026-10-05).
Enter the number of days (up to 10,000).
Choose Add (later) or Subtract (earlier).
Read the resulting date, the weekday, and the calculation steps.
The rule
Resulting date = start date ± number of days (real calendar days)
Add moves forward, subtract moves back — across month and year boundaries, following the calendar.
Example
30 days later: 30 days after 2026-10-05 = 2026-11-04, a Wednesday.
30 days earlier: 30 days before 2026-10-05 = 2026-09-05, a Saturday.
Leap year: 1 day after 2024-02-28 = 2024-02-29 (2024 is a leap year, so February has 29 days).
Things to watch
Real calendar days are counted: month lengths and leap years are handled automatically — a month is not assumed to be 30 days.
Holidays are not skipped: if the result lands on a Friday or a public holiday, move it yourself.
Gap between two dates: to find how many days lie between a start and an end date, see the day counter calculator.
Frequently asked questions
How do I add days to a date?
Count forward on the calendar from the start date. For example, 30 days after 2026-10-05 is 2026-11-04. Enter the date and the days above to get the result and the weekday.
How do I find the date 30 days ago?
Choose Subtract (earlier) and enter the number of days. For example, 30 days before 2026-10-05 is 2026-09-05.
Are leap years handled?
Yes, real calendar days are counted. For example, 1 day after 2024-02-28 is 2024-02-29, because 2024 is a leap year.
What is the maximum number of days?
10,000 days (about 27 years) in one go. Enter a smaller number if you see an error.
How do I know the weekday of the result?
The weekday is shown with the resulting date. For example, 2026-11-04 falls on a Wednesday.
Also searched as
Add days to date calculator · Subtract days from date · Date plus days calculator · What date will it be in 30 days · Days before a date calculator