Rule of three (cross multiplication)
Find the 4th value of a proportion: if A is to B, then C is to what?
How to use it
- Add your file or enter your values.
- Adjust the options if needed.
- Run it: the result appears at once and stays on your device.
FAQ
What is Rule of three (cross multiplication) for?
Find the 4th value of a proportion: if A is to B, then C is to what?
How do I use Rule of three (cross multiplication)?
1. Add your file or enter your values. 2. Adjust the options if needed. 3. Run it: the result appears at once and stays on your device.
Is my data sent anywhere?
No, the calculation runs entirely in your browser.
Is Rule of three (cross multiplication) free and unlimited?
Yes, no signup, no usage limit.
Which browsers are supported?
All modern browsers, on desktop and mobile.
Is the result accurate?
Calculations use standard formulas. For health, money or legal topics the result is indicative and does not replace professional advice.
Does Rule of three (cross multiplication) work offline?
After a first visit, most tools keep working without a connection.