This proportion calculator helps when a, b, c are already known and you want the x quickly.
Informational calculator only. Verify important outputs independently before legal, tax, medical, engineering, safety-critical, contractual, employment, or compliance use.
Enter job values, review the estimate, then use the decision hints before ordering or quoting.
a : b = c : x, so x = (b x c) / aCross-multiply the known values and divide by the remaining denominator.
This is a standard rule-of-three setup.
Keep more decimal places when the result will be reused in another formula, drawing, or comparison rather than read once and rounded.
Yes. The formula is stable and this tool only covers straightforward calculation.