Ratio and Proportion Calculator
Simplify a whole-number ratio and divide a total into proportional shares, or solve the missing value in a:b = c:x. Inspect the shares and calculation steps.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
For whole-number parts, divide each part by their greatest common divisor. Divide each part by their sum for its fraction of the total. For a:b = c:x, cross-multiply to obtain x = bc/a.
shareᵢ = total × partᵢ / Σparts; a:b = c:x ⇒ x = bc/a
Worked example
12:18:30 simplifies to 2:3:5. Sharing 150 gives 30, 45 and 75. In proportion mode, 2:3 = 10:x gives x=15.
Assumptions and input details
Ratio sharing accepts 2–20 positive whole-number parts, each at most 1e12, separated by colons, commas or spaces. Simplification is exact integer arithmetic; shares and proportions use floating-point arithmetic. The total may be zero but not negative. Proportion inputs are strictly positive and may be decimals. Shares describe divisible quantities: no whole-item allocation or currency rounding rule is applied. All parts and the total must refer to the same quantity or unit.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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