Weeks Calculator
Add or subtract weeks from any date to find a resulting date, or compute the number of weeks between two dates. Handles partial weeks with decimal precision.
About this Calculator
Add or subtract weeks from any date to find a resulting date, or compute the number of weeks between two dates. Handles partial weeks with decimal precision.
Formula & Calculations
Formula
Result Date = Start Date ± (Weeks × 7 days); Weeks Between = (End Date − Start Date) ÷ 7Where:
- Start Date=The reference date for the calculation
- End Date=The second date for calculating weeks between
- W=Number of weeks to add or subtract
Assumptions
- One week always equals exactly 7 days.
- Fractional weeks are supported (e.g., 1.5 weeks = 10.5 days).
- Leap years are automatically accounted for by the Date object.
Calculation Examples
Example 1
June 1 + 28 days = June 29, 2024.
Example 2
74 calendar days between Jan 1 and Mar 15 ÷ 7 = approximately 10.57 weeks.
Frequently Asked Questions
Can I subtract weeks?
Yes. Simply enter a negative number of weeks (or use the subtraction mode) to find a date in the past. For example, -2 weeks from today goes back 14 days.
How does the calculator handle partial weeks?
The 'Weeks Between' result shows decimal weeks (e.g., 5.43 weeks), giving you precise partial-week values. The date result mode supports whole-number weeks.
Does this account for leap years?
Yes. Adding or subtracting weeks uses JavaScript's Date object, which correctly handles all calendar transitions including leap years.