How do I use the Rule of Three Calculator?
Enter your values in the fields and the result updates instantly as you type.
Rule of Three Calculator
Solve proportions quickly: if a relates to b, find x for c.
Any numeric value (not zero)
Any numeric value
Any numeric value
Results
Formula: x = (b * c) / a
Invalid value for this calculator. Please enter valid numbers.
Frequently asked questions
What formula does this calculator use?
x = (b * c) / a
Can I use decimal values?
Yes. Decimal inputs are supported for most calculators. Integer-based tools use rounded integer values where appropriate.
Is this calculator free?
Yes. CalcuNimble calculators are free and optimized for fast everyday use.