Ratio Calculator
Simplify ratios and compute proportions.
The Ratio Calculator helps you simplify ratios to their lowest terms, solve proportions for missing values, scale ratios up or down, and check if two ratios are equivalent. Ratios express the relationship between two quantities and appear everywhere in daily life: cooking recipes (double the batch), map scales (1:50,000), financial ratios (price-to-earnings), aspect ratios (16:9 for HD video), and mixing solutions (1 part concentrate to 4 parts water). This calculator handles all standard ratio operations with clear step-by-step results.
Ratio Calculator
Formula
Examples
Simplify 24:36
Reduce the ratio 24:36 to its simplest form.
→ 2:3 (GCD = 12)
Scaling a Recipe from 4 to 10 Servings
Original recipe calls for 2:3 ratio of sugar to flour. Scale to 10 servings.
→ Scale factor: 2.5 → Sugar: 5 parts, Flour: 7.5 parts
Solve a Proportion: 5:8 = x:40
Find the missing value x in the proportion 5:8 = x:40.
→ x = 25 (because 5/8 = 25/40)
Map Scale Conversion
A map scale is 1:25,000. A distance of 4 cm on the map represents how many km in reality?
→ 4 cm × 25,000 = 100,000 cm = 1 km
Tips
- ✓Common aspect ratios: 16:9 (widescreen HD), 4:3 (standard SD), 1:1 (square), 9:16 (vertical video).
- ✓For cooking, scale all ingredients equally by multiplying by the same factor.
- ✓Always simplify ratios before comparing — 6:8 and 9:12 are both equivalent to 3:4.
- ✓Financial ratios like P/E are most useful when compared to industry peers, not in isolation.
Frequently Asked Questions
How do I simplify a ratio?
Find the Greatest Common Divisor (GCD) of both numbers and divide each by it. Example: 12:8 → GCD(12,8) = 4 → 12/4 : 8/4 = 3:2.
How do I solve a proportion for a missing value?
Cross-multiply and divide. If A:B = C:D and D is unknown: D = (B × C) / A. Example: 3:4 = 9:? → ? = (4 × 9) / 3 = 12.
How do I scale a recipe up or down using ratios?
Multiply all ingredient quantities by the same scale factor. Example: a recipe for 4 servings (2 cups flour, 1 cup sugar) scaled to 6 servings: multiply by 1.5 → 3 cups flour, 1.5 cups sugar.
What is the difference between a ratio and a fraction?
A ratio compares two related quantities (3:4 means 3 parts A for every 4 parts B). A fraction represents a part of a whole (3/4 means 3 out of 4 total). They use the same arithmetic but different conceptual interpretations.
What are common aspect ratios used in media?
16:9 — widescreen HD/4K video and monitors. 4:3 — older TV and monitors. 1:1 — square (Instagram posts). 9:16 — vertical video (stories/reels). 21:9 — ultrawide monitors.
What is a financial ratio?
Financial ratios compare two financial figures to assess performance. Common examples: P/E ratio (price-to-earnings), debt-to-equity ratio, current ratio (current assets / current liabilities). They help compare companies of different sizes.