Add or Subtract Days Calculator

Formula & Calculation Methodology

Target Date = Base Date ± Offset Days. Automatically adjusts for leap years and month lengths.

Step-by-Step Worked Example

Base Date: 15 August 2026 | Operation: Add 45 Days

1. 1. Add 45 calendar days to August 15, 2026
2. 2. Remaining days in August = 16 days (till 31 August)
3. 3. Remaining 29 days fall in September
4. 4. Resulting Target Date = 29 September 2026 (Tuesday)

Calculate Future and Past Dates Effortlessly

Whether calculating invoice payment due dates, project deadlines, pregnancy due dates, visa validity periods, or notice period end dates, this tool provides instant calendar date additions and subtractions.

Frequently Asked Questions