How to use the Add or Subtract Days
- Choose a start date (today by default).
- Choose add or subtract.
- Enter the amount and pick days, weeks, months or years.
- Read the resulting date and weekday.
What does this tool do?
Adding days and weeks is exact. Adding months follows the calendar: March 15 plus one month is April 15. When the target month is shorter, the result moves to its last day — January 31 plus one month is February 28 (or 29).
Why use it?
- Deadlines like “30 days from today”.
- Warranty and return windows.
- Medication and follow-up schedules.
Example
90 days after October 4, 2026 is Saturday, January 2, 2027.
Privacy
The calculation happens instantly in your browser. The numbers you enter are not sent to our servers or saved. There's no account to create and nothing to install.
Frequently asked questions
What date is 90 days from now?
Enter today's date and add 90 days. Because months have different lengths, 90 days isn't the same as three months — 90 days from January 1, 2026 is April 1, 2026.
Is the start date counted?
No. Adding one day to Monday gives Tuesday, the same way you'd count on a calendar.
Last reviewed by the M2Toolkit team.