Add Days to Date Calculator

Add or subtract days, weeks, or months from any date. Perfect for calculating deadlines, due dates, and future events.

Add or Subtract Days from a Date

How the Calculation Works

How It Works: Enter a start date and the number of days, weeks, or months to add (or subtract if negative). The calculator computes the new date, accounting for leap years and varying month lengths.

Worked Example

Example 1: Start date September 1, 2026, add 90 days:

  • Result: November 30, 2026

Example 2: Start date September 1, 2026, add 3 months:

  • Result: December 1, 2026

How to Use This Calculator

Uses: Calculating project deadlines, predicting due dates, scheduling future events, or planning delivery dates.

Frequently Asked Questions

How do I add days to a date?

Enter your start date and the number of days to add. The calculator shows the resulting date.

Can I subtract days?

Yes, use negative numbers. Enter -7 to subtract a week, for example.