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Ratio Calculator: Simplify, Solve and Share a Total

This free ratio calculator simplifies ratios, solves missing values in a proportion, and splits any total into parts that follow a ratio such as 2:3:5.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

A ratio compares quantities of the same kind. A paint mix of 2 parts blue to 3 parts white is the ratio 2:3. Ratios appear in recipes, maps, finance, gearing and sharing profits. People most often need to reduce one, find a missing value, or divide a sum by a ratio.

Pick the job, fill the boxes and the tool prints both the answer and the arithmetic.

How to Use This Tool

  1. Choose simplify, solve or share.
  2. For simplify, type the ratio with colons, such as 12:18:30. For the other modes, fill in the labelled boxes.
  3. Press Calculate.
  4. Check the working lines under the answer.

How the Calculation Works

Simplify: divide each part by the GCD of all parts. Proportion: from A/B = C/X, X = B × C ÷ A. Share: one part = total ÷ (sum of parts), and each person gets their part × one part.

Worked Example

Simplify 36:48:60. The GCD is 12, so the ratio is 3:4:5. To scale a recipe, solve 2 : 5 = 7 : X. Then X = 5 × 7 ÷ 2 = 17.5. To divide 9,000 between two partners 4:5, one part is 1,000, so they receive 4,000 and 5,000.

Common Uses

  • Mixing paint, concrete or cooking ingredients.
  • Dividing profit between partners.
  • Reading map and drawing scales.
  • Aspect ratios of images and screens.

Tips and Common Mistakes

  • Keep the same units on both sides of a ratio.
  • Order matters: 2:3 is not the same as 3:2.
  • A ratio can be written as a fraction: 2:3 means 2/3 of the second amount.

Next, you may need the fraction calculator, percentage calculator, GCD and LCM calculator, weighted average calculator.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

Divide every part by the greatest common divisor of all the parts. 12:18:30 divided by 6 becomes 2:3:5.
Cross-multiply. X = B × C ÷ A. For 4 : 6 = 10 : X, X = 6 × 10 ÷ 4 = 15.
Add the parts of the ratio, divide the total by that sum to get one share, then multiply by each part. 1,000 shared 2:3:5 gives 200, 300 and 500.
Yes for the proportion and share modes. The simplify mode works with whole numbers; decimals are scaled up to whole numbers first.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.