Lowest terms instantly
Divides both parts by their greatest common divisor, so 12:16 becomes 3:4 with the divisor shown.
CalculatorsRuns in your browser
Ratio Calculator (Simplify & Scale)
Simplify a ratio, see each share as a percentage, and scale it up.
- Input
- No upload needed — instant
- Privacy
- Nothing is uploaded
- Cost
- Free · no sign-up · no watermark
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Overview
About the Ratio Calculator (Simplify & Scale)
Simplify a two-part ratio to its lowest terms, see each side as a percentage of the total and as a decimal, and list equivalent scaled-up ratios.
A ratio compares two quantities. This calculator reduces any two-part ratio to its simplest form, shows what each side is worth as a percentage of the total, and lists equivalent ratios so you can scale it to the size you need.
Simplifying
12 : 16 → GCD 4 → 3 : 4Both parts are divided by their greatest common divisor. When the GCD is 1 the ratio cannot be reduced further.
Parts versus whole
In 3:4 there are 7 parts in total, so A is 3/7 ≈ 42.86% and B is 4/7 ≈ 57.14%. That is different from the fraction 3/4 = 75%, which treats B as the whole — the calculator shows the ratio value A ÷ B and each share of the total so both readings are clear.
Private and instant
Everything is computed in your browser with exact integer arithmetic. Nothing is uploaded and no account is needed.
Step by step
How to use the Ratio Calculator (Simplify & Scale)
Enter the two parts of the ratio, A and B.
Read the simplified ratio and each side's share as a percentage.
Use the equivalent-ratios table to scale the ratio up or down.
Why use it
Benefits and common use cases
What this tool is good for, and what it deliberately does not try to do.
Shares as percentages
Turns each part into its share of the total, which is how ratios are used for splits, recipes and aspect ratios.
Scale it up
An equivalent-ratios table multiplies the simplified ratio by 2, 3, 5 and 10 so you can match any quantity you need.
Questions
Frequently asked questions
Short, honest answers about quality, limits and privacy.
How do you simplify a ratio?
Divide both parts by their greatest common divisor. For 12:16 the GCD is 4, giving 3:4. If the GCD is 1 the ratio is already in its lowest terms.
Is a ratio the same as a fraction?
Related but different. The ratio 3:4 compares two parts out of 7 in total, while the fraction 3/4 is three parts of one whole divided into four. The calculator shows both the ratio value (A ÷ B) and each share of the total.
How is this used for aspect ratios?
Screen and image aspect ratios like 16:9 are simplified ratios of width to height. Enter the pixel dimensions to reduce them, then scale to find equivalent sizes.