Proportion Solver
Free Proportion Solver calculator with clear step-by-step results.
About Proportion Solver
Solves for the missing term in a proportion.
Formula
Formula
d = b × c ÷ a (from a/b = c/d)
Worked example
With the default values below, Proportion Solver returns d (unknown) of 20.000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- a (from a/b)
- 2
- b (from a/b)minimum 0
- 5
- c (from c/d)
- 8
Results
- d (unknown)
- 20.000
- Ratio a:b
- 2:5
- Cross Check
- 40.000
Step by step
- 1Values used
- 2Formula
- 3d (unknown)= 20.000
- 4Ratio a:b= 2:5
- 5Cross Check= 40.000
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How does this calculator work?
Solves for the missing term in a proportion.
Why does this matter?
Cross-multiplication keeps the ratio consistent.