Ratio Calculator
Simplify any ratio to its lowest terms, or scale it up to match a target. Useful for recipes, mixing proportions, map scales, and pretty much anything involving a proportion.
How to use
- Enter the two sides of your ratio.
- If you want to scale it, type a target value for one side and the other side will adjust.
- Click Calculate to get the simplified ratio and scaled values.
Related tools:
A ratio compares two or more quantities. 3:5 means for every 3 of the first thing, there are 5 of the second. Ratios can be simplified by dividing all parts by their GCD: 12:18 simplifies to 2:3. They can also be scaled: if a recipe serves 4 in a 2:3 flour-to-sugar ratio and you want to serve 10, scaling the ratio tells you the new quantities.
Ratios appear in cooking, mixing paint or concrete, map scales, screen resolutions, and financial analysis (debt-to-equity, price-to-earnings). The key idea is that ratios express a relationship, not absolute amounts - 2:3 and 200:300 say the same thing about the proportion.
Frequently Asked Questions
How do I simplify a ratio?
Find the GCD of all parts and divide each by it. Ratio 24:36:48: GCD is 12, so simplified is 2:3:4. The proportional relationship is identical to the original.
What is the difference between a ratio and a fraction?
A fraction represents one quantity as a part of a whole (3/8 means 3 out of 8 total). A ratio compares two separate quantities (3:8 could mean 3 of one thing and 8 of another, with 11 total - or it could represent a part-to-whole relationship like a fraction). Context matters.
How do I use ratios in a recipe?
Find the scaling factor: new servings / original servings. Multiply each ingredient by this factor. If the ratio between ingredients changes, the recipe changes. The ratio calculator scales all parts proportionally.