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Numio

Rule of Three Calculator (Dreisatz with Steps) — Numio

Solve direct and inverse proportion problems with the rule of three, showing each calculation step. Runs in your browser.

Convert in your browser · No sign-up

Solves a rule-of-three problem and shows the calculation step by step.

Up to 100,000 UTF-16 units per input and 1,000,000 per result. See the supported formats and examples below.

Result

Add your input or load an example, then run the tool. Your result will appear here.

How to use

  1. Choose Direct when more gives more, or Inverse when more gives less.
  2. Type the three known values as A, B and C.
  3. Read the result and the calculation steps.

Example

3 : 6 = 5 : x → Result: 10

Details and limitations

Direct: x = C · B / A. Inverse: x = A · B / C.

Results that are not whole numbers are shown with up to six decimal places.

FAQ

What does A, B and C mean?

In a standard set-up, A and B are the first pair and C is the known value of the second pair. The result is x.

Is my data uploaded?

No. The calculation runs in your browser.

Format references

Tool page updated: