Simplify ratios, find equivalent ratios, and scale values instantly with our free Ratio Calculator. Ideal for maths, recipes, construction, engineering, maps, and everyday calculations. Fast, accurate, and easy to use on desktop and mobile devices.
✔ Simplify ratios • ✔ Scale recipes & mixtures • ✔ Accurate results • ✔ Free online calculator
A ratio calculator helps compare two values and simplify them into their lowest form. Ratios are used to show the relationship between quantities and are commonly written using a colon, such as 2:3 or 5:1.
This calculator automatically simplifies ratios by finding the greatest common divisor (GCD) of both numbers and reducing them to the smallest possible whole-number ratio.
Whether you're scaling a recipe, comparing financial figures, mixing materials, or solving a maths problem, a ratio calculator can save time and reduce calculation errors.
A ratio compares one quantity to another. For example:
Ratios do not necessarily represent percentages. Instead, they show proportional relationships between quantities.
To simplify a ratio, divide both values by their Greatest Common Divisor (GCD).
Formula:
Simplified Ratio = (A ÷ GCD) : (B ÷ GCD)
Example:
A recipe uses 200g flour and 100g sugar.
This means you need twice as much flour as sugar regardless of batch size.
A two-stroke engine requires a 50:1 fuel mixture.
For 5 litres of petrol:
Ratios are used in many everyday situations:
Understanding ratios can make it easier to compare quantities and make informed decisions.
People often confuse ratios and percentages, but they are different.
| Ratio | Percentage |
|---|---|
| 2:5 | 40% |
| 1:4 | 25% |
| 3:4 | 75% |
Ratios compare quantities directly, while percentages compare a value to 100.
This calculator helps avoid these mistakes by automatically simplifying ratios.
| Original Ratio | Simplified Ratio |
|---|---|
| 10 : 20 | 1 : 2 |
| 15 : 45 | 1 : 3 |
| 24 : 36 | 2 : 3 |
| 50 : 100 | 1 : 2 |
| 75 : 125 | 3 : 5 |
| 90 : 120 | 3 : 4 |
| 120 : 180 | 2 : 3 |
What is a ratio?
A ratio compares two quantities and shows their proportional relationship.
Can ratios contain decimals?
Yes. However, ratios are often converted into whole numbers for easier comparison.
Can I use ratios for recipes?
Yes. Ratios are widely used in cooking and baking to scale ingredients accurately.
What is the simplest form of a ratio?
The simplest form is obtained when both numbers can no longer be divided by the same whole number.
Is a ratio the same as a fraction?
No. Ratios compare quantities, while fractions represent part of a whole.
Why simplify ratios?
Simplified ratios are easier to understand, compare, and use in calculations.
Quickly calculate percentages and changes.
Perform addition, subtraction, multiplication and division.
Work out sale prices and savings during promotions.
Calculate gratuities and split restaurant bills.
Simplify and scale ratios for recipes, maths and business.
Calculate mean, median and mode instantly.
Find the number of days, months or years between two dates.
Count business days while excluding weekends and holidays.
See exactly how much time remains until any future date or event
Measure elapsed time accurately with an easy-to-use online stopwatch
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Last Updated: August 2026