MultiConvers

Ratio Calculator

Reduce a two-part comparison A:B to lowest terms and see A ÷ B as a decimal — maps, recipes and mixing, not a percentage of a whole.

How to use

  1. Enter the first quantity as A and the second as B. Decimals are allowed.
  2. Read the simplified ratio and the decimal A ÷ B.
  3. Scale the simplified pair if you need a batch: 2:3 with 10 on the A side is 10:15.
  4. Use GCF if you only want the divisor, or the percentage page if the question is “what share of a total.”

How it works

A ratio says how two amounts sit next to each other, not how one sits inside a total. 8:12 of concentrate to water simplifies to 2:3. That is the same mix as 200 ml : 300 ml. The decimal 8 ÷ 12 ≈ 0.6667 is A per one unit of B, not “66.67% of the drink” unless you also add the parts (2 + 3 = 5, so concentrate is 2/5 = 40%).

Decimals are scaled to integers before the GCD step. 2.5:10 becomes 5:20 then 1:4. 0.2:0.8 becomes 1:4 as well.

B = 0 gives a simplified 1:0 (or n:0 reduced) and no decimal — you cannot divide by zero. 0:5 is 0:1 with decimal 0. 0:0 is rejected; there is no unique lowest terms.

Aspect ratios (16:9) and gear teeth are the same arithmetic. This page does not lock the result to integers on the decimal side; 2:3 shows 0.666667 at the stated precision.

It is not a three-part ratio and not a percentage calculator. “2 in every 3 students” is 2:3 here, or 66.67% on the other page if you treat 3 as the whole.

Formula

Simplified A:B = (A ÷ gcd, B ÷ gcd) after scaling decimals to integers
Decimal = A ÷ B

Worked examples

  • 8:12 in lowest terms

    8 and 12 → 2 : 3, decimal 0.666…

  • A decimal pair

    2.5 and 10 → 1 : 4, decimal 0.25

Useful notes

  • 2:3 is not automatically 66.67% of a whole — add the parts first.
  • 0:0 cannot be simplified.
  • Signs follow the numbers you typed; mixing usually uses positives.

FAQ

How do I simplify a ratio?

Divide both numbers by their greatest common divisor. 8 and 12 share 4, so 8:12 = 2:3.

What does the decimal mean?

It is A divided by B. 2:3 is about 0.6667. It is not “2.3” or a mixed number.

Can one side be zero?

5:0 simplifies to 1:0; the decimal is undefined. 0:5 becomes 0:1 with decimal 0. 0:0 is rejected.

How do I scale 2:3 up to 12 on the first side?

12 ÷ 2 = 6, so multiply both parts by 6: 12:18. The decimal stays 0.666…

Is 16:9 the same as 1.777…?

Yes — that decimal is 16 ÷ 9. The simplified ratio stays 16:9 because 16 and 9 share no common factor greater than 1.

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