Add days to a date
Add or subtract days from a date and find the resulting date and weekday. Includes weekends, holidays and leap years, with no registration.
Choose a starting date and a whole number of days: positive to add, negative to subtract. The starting date is day zero. All calendar days count, including weekends and holidays.
Result
Enter your data and run the tool. Your result will appear here.
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How to add or subtract days
Enter a starting date and the number of days. The result shows the final date, weekday and unambiguous ISO YYYY-MM-DD format for copying.
Does the starting day count?
Adding 0 days returns the same date. Adding 1 gives the following day. The starting date is not counted as day one. Use a negative number to move backwards.
Examples across months and leap years
January 1, 2026 plus 30 days is January 31, 2026. February 28, 2024 plus 2 days is March 1, 2024 because 2024 is a leap year. March 1, 2024 minus 1 day is February 29.
Calendar days versus working days
The calculation uses the proleptic Gregorian calendar for years 0001–9999, without reproducing historical national calendar reforms. Time zones and daylight saving do not affect the result.
To exclude weekends and holidays, use the working-days calculator. Legal or administrative deadlines may follow special rules that this date addition does not determine.
Frequently asked questions
Can I subtract days?
Yes. Enter a negative whole number, such as −10, to go back ten days.
Are weekends and holidays included?
Yes. All calendar days count. Use the separate working-days tool for exclusions.
Is the starting date included?
It is day zero: date + 0 stays the same, while date + 1 gives the next day.