Add or Subtract Days to a Date
Find the date that is a number of days, weeks, months or years before or after another date — or count business days only.
Result
Enter your values and select Calculate to see the result.
How to use this calculator
- Choose the start date (defaults to today) and whether to add or subtract.
- For calendar time, fill in any mix of years, months, weeks and days.
- For business days, enter a number of working days; weekends are skipped.
Formula
Years and months are applied first, then weeks and days.
Month-end rule: if the day does not exist in the target month, the last day of that month is used, so 31 January + 1 month = 28 or 29 February. This matches spreadsheet functions such as EDATE.
Business days: the start date is not counted; each step moves one day and only Monday–Friday count. Public holidays are not excluded.
Worked example
90 days from 1 January 2025
January has 31 days, February 28 and March 31, so day 90 after 1 January lands on 1 April 2025.
One month after 31 January 2024
February 2024 has 29 days, so the result is 29 February 2024.
10 business days
From Monday 6 January 2025, 10 business days later is Monday 20 January 2025.
Assumptions and limitations
- Uses the Gregorian calendar.
- Public holidays vary by country and are not taken into account for business days.
- Times of day are ignored.
Frequently asked questions
Is “30 days” the same as “1 month”?
No. A month is 28 to 31 days. Contracts and deadlines usually say which they mean, so enter the right unit.
Does the start date count?
No. Adding 1 day to Monday gives Tuesday. Use the Days Between Dates calculator if you need to count both endpoints.