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Ratio Calculator

Use this ratio calculator to simplify a ratio and scale it to a new first value.

Primary answer
Matching second value
Inputs to verify
First ratio value, Second ratio value, and New first value
Use type
Use as a direct calculation check.
Keyword intent
ratio calculator

Calculator

Ratio Calculator

Calculates matching second value from first ratio value, second ratio value, new first value. Defaults are filled in so you can review a working example before changing inputs.

Must be nonzero.

Paired value in the ratio.

Scale the ratio to this first value.

Result

Result reflects the current submitted inputs.

  • Risk A
  • Reviewed 2026-05-26
  • 1 sources
Matching second value15
Simplified ratio2:3
Scale factor2.5
  • The first ratio value cannot be zero.
  • Simplification rounds only integer-like ratios.

Accuracy notes

Risk level
A
Reviewed
2026-05-26
Sources
1
Primary result
Matching second value

Formula logic is kept in a pure calculator module with fixtures, source notes, and page-visible assumptions.

Categories

What the result means

The matching second value keeps the same proportion. The simplified ratio shows the smallest equivalent integer ratio when possible.

Matching second valueDisplayed as decimal.
Simplified ratioDisplayed as text.
Scale factorDisplayed as decimal.

Use the result this way

  1. Start with Matching second value, then use supporting outputs for context.
  2. Verify First ratio value, Second ratio value, and New first value before copying the result.
  3. Check the formula, example, and assumptions before reusing the answer.

User job

How to use this calculator

Use Ratio Calculator when you need matching second value, then use simplified ratio and scale factor to check the context for quick number work, classwork, spreadsheet checks, and explaining a calculation to someone else.

Best for

  • Checking the core numeric relationship
  • Comparing the main result with supporting outputs
  • Reviewing a default example before entering your own first ratio value and second ratio value.

Check before relying

  • Confirm sign, decimal, percent, and rounding assumptions before copying the number.
  • The first ratio value cannot be zero.
  • Simplification rounds only integer-like ratios.
  • Source context: Wikipedia, reviewed 2026-05-26.

Next useful step

Formula

Scale factor = new first value / original first value. Matching second value = original second value x scale factor.

  • Scale factor = new first value / original first value. Matching second value = original second value x scale factor.
  • Enter First ratio value, Second ratio value, and New first value. The first original value must not be zero.
  • Last reviewed: 2026-05-26.

Inputs

Enter First ratio value, Second ratio value, and New first value. The first original value must not be zero.

First ratio valueMust be nonzero.
Second ratio valuePaired value in the ratio.
New first valueScale the ratio to this first value.

Example

A 4:6 ratio simplifies to 2:3. If the first value is scaled to 10, the matching second value is 15.

FAQ

How do I simplify a ratio?

Divide both values by their greatest common divisor. For example, 4:6 simplifies to 2:3.

How do I find an equivalent ratio?

Multiply both parts of the ratio by the same scale factor so the relationship between the two values stays unchanged.

Can the first ratio value be zero?

No. The calculator divides by the first value to find the scale factor, so zero would make the ratio undefined.

Can ratios use decimals?

Yes. Decimal ratios can be scaled, but simplification is most useful for integer-like ratios where a common divisor is meaningful.

What should I verify before using ratio calculator?

Verify first ratio value, second ratio value, and new first value, the displayed formula, and the worked example before copying the result into another document or decision.

What is the main output of ratio calculator?

Matching second value is the first value to read. Use the supporting outputs and assumptions to understand why it changed.

Sources

Last reviewed: 2026-05-26

  • Reviewed 2026-05-26
    Ratio definitionWikipedia. General reference for ratios and proportional relationships.