Add or Subtract Days from a Date
Add or subtract days, weeks, months, years or business days from a date and see the resulting weekday, with the month-end rule explained. Free and in your browser.
How to use Add or Subtract Days from a Date
- 1Enter the start date, or press Today.
- 2Choose Add or Subtract and fill in any of years, months, weeks, days and business days.
- 3Read the result date and weekday, or switch mode to compare two dates or work out an age.
What makes it better
- Years, months, weeks, days and business days can be combined in a single calculation
- Month-end clamping is applied and explained, for example 31 January + 1 month = 29 February 2024
- Business days skip Saturdays and Sundays and work from a weekend start date too
- Shows the weekday of the result and how many calendar days were moved
- Dates beyond year 9999 work; results past year 999,999 are refused with a message
About Add or Subtract Days from a Date
Start from any date and add or subtract days, weeks, months, years or business days in one go to get the resulting date and its weekday. Months and years are applied first with month-end clamping, so 31 January plus one month lands on the last day of February, and the page spells out when that happened. The same page also finds the difference between two dates and calculates an age.
Common uses
- Find the due date for an invoice that is payable 45 days after issue.
- Count 10 business days forward from a request to get a delivery or response date.
- Work out a contract end date that is 18 months after the start.
- Step back from an event date to find when a 6-week plan must begin.
Example
Input
2024-01-31 + 1 month + 10 days
Result
Start: 2024-01-31 (Wednesday) Add: 1 month, 10 days Result: 2024-03-10 (Sunday) Long form: Sunday, 10 March 2024 Days moved: 39 Month-end rule: 2024-01-31 + 1 month: February 2024 has only 29 days, so the day moved to 29 (the last day of that month) instead of 31.
Good to know
- Order of operations: years and months first, then weeks and days, then business days. Changing the order could change the result around month ends, so the page keeps it fixed.
- Business days exclude weekends only; public holidays and regional weekends are not known. If the start date is a weekend, the first business day counted is the next weekday in the direction of travel.
- Amounts must be whole numbers of 0 or more. Use the Subtract option to move backwards instead of typing a minus sign.
Add or Subtract Days from a Date FAQ
How do I add days to a date?
Enter the start date and type the number of days under Days, then read the result. Weeks, months and years can be added in the same calculation, and the weekday of the answer is shown beside it.
What is the date 90 days from today?
Press Today for the start date, enter 90 under Days and the result shows immediately. Today comes from your device clock when you press the button, so no date is assumed in advance.
What happens when I add a month to the 31st?
If the next month is shorter, the day is moved back to that month's last day, so 31 January plus one month is 29 February in a leap year and 28 February otherwise. The page prints a note whenever this adjustment happens.
How do I add business days to a date?
Fill in Business days. Each step moves to the next Monday-to-Friday day, so 1 business day from a Friday is the following Monday. Holidays are not excluded, so add extra days for those.
Can I subtract days or months instead?
Choose Subtract under Direction and the same amounts are taken away. Subtracting a month from 31 March lands on the last day of February, using the same end-of-month rule as adding.