Proportion Calculator

Proportion solver — enter known values to find the unknown, supporting both A:B = C:D and A/B = C/D forms.

Proportion Solver A / B = C / D
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Proportion Scaling

Scale a value by a ratio — enter the original value and scaling ratio to compute the scaled result.

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Proportion Simplifier

Reduce a ratio to its simplest integer form.

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Features

The proportion calculator provides three common proportion calculation features to quickly solve proportion-related problems.

  • Proportion Solver: Given three of A:B = C:D, automatically find the fourth
  • Proportion Scaling: Scale a value by a specified ratio
  • Proportion Simplifier: Reduce a ratio to its simplest integer form

Usage Instructions

Features

The proportion calculator integrates proportion solving, scaling and simplifying — find the fourth value from three known values in A:B=C:D, scale values by a ratio, or reduce a ratio to simplest integers.

Steps

In "Proportion Solver", enter any three of A, B, C, D (leave the unknown blank) and click "Solve"; or in "Proportion Scaling", enter the original value and the old/new ratios to compute the scaled result; or in "Proportion Simplifier", enter two numbers to reduce to the simplest integer ratio.

Notes

All calculations run locally in the browser; denominators cannot be zero when solving; the simplifier supports decimal-to-integer conversion and results keep up to 8 decimal places.