Enter a ratio to simplify:
:
Supports decimals — e.g. 1.5 : 2.25
Ready to calculate
Enter values and click Calculate// simplify and scale ratios instantly
Free online ratio calculator. Simplify ratios to lowest terms, scale ratios to a target value, and compare multiple ratios instantly in your browser.
Supports decimals — e.g. 1.5 : 2.25
Ready to calculate
Enter values and click CalculatePick Simplify, Scale, or Compare from the tabs above.
Type the ratio parts (decimals are supported too).
Instantly see the simplified form, scaled result, or comparison.
A ratio calculator lets you reduce ratios to their simplest form using the Greatest Common Divisor (GCD), scale both parts proportionally to a target value, or verify whether two ratios are mathematically equivalent.
Simplifying a ratio means dividing both parts by their Greatest Common Divisor (GCD) until no whole number greater than 1 divides both evenly. For example, 12:8 simplifies to 3:2.
Yes. The calculator converts decimals to equivalent integers internally before applying GCD reduction. For example, 1.5:2.25 is treated as 150:225, which simplifies to 2:3.
You choose which part (A or B) you want to reach a specific value, and the calculator multiplies both parts by the required factor. This preserves the proportion while hitting your target.
Two ratios A:B and C:D are equivalent if A÷B = C÷D (i.e. their decimal forms are equal). The Compare mode checks this precisely and shows you the decimal value of each ratio.
The GCD (Greatest Common Divisor) is the largest integer that divides both ratio parts without remainder. Dividing both parts by the GCD gives the simplest form of the ratio.
All calculations are done client-side in your browser using JavaScript. No data is transmitted to any server, making this tool completely private and offline-capable after the page loads.
A ratio expresses the relationship between two quantities, showing how many times one value contains or is contained within another. Ratios appear everywhere — in cooking, architecture, finance, science, art, and engineering. A ratio calculator automates the tedious arithmetic involved in working with ratios, letting you simplify, scale, and compare ratios in seconds.
💡 Looking for premium web development assets? MonsterONE offers unlimited downloads of templates, UI kits, and design assets — worth checking out.
The most common ratio operation is simplification — reducing 12:8 to 3:2, or 100:75 to 4:3. The mathematical process relies on the Greatest Common Divisor (GCD), also called the Greatest Common Factor (GCF). By dividing both parts of the ratio by their GCD, you arrive at the simplest equivalent form where no integer greater than 1 divides both parts evenly.
For example:
Simplified ratios are easier to communicate, compare, and work with in formulas. Our calculator handles decimal inputs too — it internally multiplies decimals to integers before applying GCD, so 1.5:2.5 correctly simplifies to 3:5.
Sometimes you know the ratio and need to scale it up or down. Common scenarios include:
The Scale mode lets you lock one part to a specific value and automatically calculates the other. This is essentially finding the missing term in a proportion: A:B = X:Y.
Two ratios are equivalent if they simplify to the same form — meaning their decimal representations are equal. For instance, 2:3, 4:6, 6:9, and 8:12 are all equivalent ratios. The Compare mode evaluates two ratios and tells you whether they are equivalent, which is useful when verifying proportional relationships in data, design specifications, or scaled drawings.
A ratio A:B can also be expressed as the fraction A/B, or as a percentage showing what portion of the total each part represents. For example, a 3:1 ratio means Part A is 75% of the total and Part B is 25%. Our simplified output includes the decimal form and the percentage breakdown for Part A, giving you multiple perspectives on the same relationship.
Architecture and Design: Architects use ratios to maintain proportional relationships — the golden ratio (approximately 1:1.618) appears in building facades, window placements, and interior layouts. Screen aspect ratios like 16:9 or 4:3 define the dimensions of displays and video content.
Chemistry and Pharmacology: Drug formulations, chemical mixtures, and dilutions are all expressed as ratios. Correctly scaling these ratios is critical for safety and efficacy. A 1:10 dilution means 1 part solute to 10 parts solvent.
Finance and Economics: Price-to-earnings (P/E) ratios, debt-to-equity ratios, and liquidity ratios are all fundamental metrics that analysts simplify and compare across companies.
Photography and Videography: Image sensors, prints, and video formats all use specific aspect ratios. Converting between 3:2 (standard camera), 16:9 (widescreen video), and 1:1 (square social media) requires ratio scaling.
This calculator uses the Euclidean algorithm to compute the GCD — one of the oldest algorithms in mathematics (attributed to Euclid around 300 BCE). The algorithm works by repeatedly taking the remainder of division until the remainder is zero. The last non-zero remainder is the GCD. For integers 48 and 18: 48 mod 18 = 12, then 18 mod 12 = 6, then 12 mod 6 = 0. GCD = 6. So 48:18 simplifies to 8:3.
For decimal inputs, the tool multiplies both values by a power of 10 to eliminate decimal places before applying the Euclidean algorithm, ensuring accurate results even with fractional inputs like 0.5:1.25.