Free Online Ratio Calculator
Simplify ratios to lowest terms, solve for missing proportional values (A:B = C:D), and scale aspect ratios for screen resolution, recipes, and geometry.
Ratio Simplification
Reduce complex integer and decimal ratios to their simplest lowest whole-number terms.
Solve for Missing X
Solve equivalent proportions with ease using cross-multiplication (A:B = C:X).
Aspect Ratio Scaling
Scale screen dimensions, photography canvas sizes, and recipe ingredient batches.
Understanding Ratios and Mathematical Proportions
A ratio expresses the quantitative relationship between two numbers, indicating how many times the first value contains the second. Proportions state that two ratios are mathematically equal. They are ubiquitous in graphic design, photography aspect ratios (16:9, 4:3), cooking, and chemistry.
Select ratio simplification (A:B) or 4-value proportion solving (A:B = C:D).
Input your integers or decimals into the corresponding terms.
Get the reduced lowest-terms answer and exact missing variable value.