Free online ratio calculator: simplify ratios to their lowest terms or find missing values in proportions. Perfect for math homework, recipe scaling, and engineering proportions. Mac OS 9 retro style.
Select 'Simplify Ratio' to reduce a ratio to its simplest form, or 'Find Missing Value' to solve a proportion (A:B = C:D) for an unknown value.
In Simplify mode, enter the two numbers (A and B) of your ratio. In Find mode, enter any three of the four values (A, B, C, D) and leave the unknown field blank.
Press Calculate to get your result. For Simplify, you'll see the ratio reduced to its lowest terms. For Find mode, the missing value is computed using cross-multiplication.
Apply your simplified ratio or solved proportion to your project, recipe, or math problem. Click Clear to start over.
Q: What does it mean to simplify a ratio?
A: Simplifying a ratio means reducing it to its lowest terms by dividing both numbers by their greatest common divisor (GCD). For example, 8:12 simplifies to 2:3.
Q: How do I find a missing value in a proportion?
A: Use cross-multiplication: if A:B = C:D, then A × D = B × C. If you know any three values, you can solve for the fourth. For example, if 2:3 = 6:D, then D = (3 × 6) / 2 = 9.
Q: Can this calculator handle decimals?
A: This calculator currently works with whole numbers only. For decimal ratios, multiply all numbers by a power of 10 to convert them to whole numbers first, then use the calculator.