Add or Subtract Days from a Date
Shift any date forward or backward by days, weeks, or months. Results use the UTC calendar so they stay consistent everywhere.
Enter a start date.
How it works
Choose a start date, whether to add or subtract, and an amount in days, weeks, or months. Weeks are converted to 7-day steps; months move by calendar month with end-of-month clamping (for example, January 31 plus one month becomes February 28 or 29).
All calculations use UTC midnight dates. For counting working days only, use the Business Days Calculator. To measure the span between two dates, try Days Between Dates.
Examples
Pick add or subtract, then enter a whole number. The result is always a single calendar date in UTC.
Add 10 days
Starting 2025-06-01 and adding 10 days gives 2025-06-11 on the UTC calendar.
Subtract 2 weeks
Two weeks means 14 calendar days backward from your start date.
Add 1 month from Jan 31
January 31 plus one month lands on February 28 in a common year (or February 29 in a leap year)—not March 2 or 3.
FAQ
- How are weeks handled?
- Weeks are always 7 calendar days. They do not skip weekends; use the Business Days Calculator for weekday-only shifts.
- What does month clamping mean?
- When adding months would land on a day that does not exist (like February 31), the result uses the last valid day of that month instead.
- Can I subtract months?
- Yes. Choose subtract and pick months as the unit—the same end-of-month rules apply in reverse.