Ratio Calculator
Simplify ratios to their lowest form, find missing values in proportions, and scale ratios up or down.
Simplify Ratio
Solve Proportion (A:B = C:D)
About the Ratio Calculator
A ratio expresses the proportional relationship between two or more quantities, written as A:B (or as a fraction A/B). Ratios are foundational across everyday applications, from cooking and photography aspect ratios to mechanical gear ratios, chemical solutions, and financial liquidity benchmarks.
This ratio calculator allows you to simplify ratios to their lowest terms by dividing each value by their greatest common divisor (GCD), scale ratios up or down by any custom multiplier, and solve for an unknown fourth variable in proportion equations (A/B = C/D) through cross-multiplication.
Understanding ratios versus proportions is key. A ratio compares two parts to one another (e.g. 3 parts water to 1 part concentrate), while a proportion expresses the relationship between a part and the whole (1 part concentrate out of 4 total parts, or 25%). When dividing a quantity according to a ratio, add the parts together first to determine the total denominator.
Suppose a concrete mix requires 1 part cement, 2 parts sand, and 3 parts gravel (a 1:2:3 ratio). To produce a batch using 50 kg of cement, multiply each component by 50: 50 kg cement, 100 kg sand, and 150 kg gravel, yielding 300 kg of total concrete mix.
Tips for best results
- To divide an amount into a ratio (such as sharing £600 in the ratio 2:3), sum the parts (2 + 3 = 5), divide the total (£600 ÷ 5 = £120 per part), and multiply each ratio number: £240 and £360.
- Always simplify ratios before performing multi-step scaling to keep numbers manageable.
- Ensure both values share the same units of measurement before calculating (e.g. convert meters to centimeters before taking a ratio against centimeters).
How to use the Ratio Calculator
Why use Toolseza for Ratio Calculator?
Use this tool as often as you need with no paywalls, premium tiers, or hidden daily calculation quotas.
All calculations and file manipulations run inside your web browser. Your inputs are never sent to a cloud server.
Results update in real-time as you type or adjust settings, with instant one-click copy and export capabilities.
Works natively on smartphones, tablets, laptops, and desktop computers with zero installation or account creation.
Editorial Standards & Verification: All formulas, algorithms, and conversion factors implemented on Toolseza adhere to openly documented international standards (ISO, NIST, BIPM, W3C). Results are verified against benchmark reference datasets before publication.
Frequently Asked Questions
Is Ratio Calculator free to use?
Yes — Ratio Calculator is completely free, unlimited, and requires no sign-up.
How do I simplify a ratio?
Find the greatest common divisor (GCD) of both numbers and divide each by it. Example: 6:9 → GCD is 3 → simplified ratio is 2:3.
Are the calculations accurate?
Yes — it uses the standard, widely accepted formula, so results are accurate and reliable.
Does it work on mobile and tablet?
Yes — Ratio Calculator works on any modern browser, including mobile and tablet, no app required.