Contrast Ratio Calculator

Formula

The formula to calculate the Contrast Ratio (cr) is:

\[ \text{cr} = \frac{L1 + 0.05}{L2 + 0.05} \]

Where:

\(\text{cr}\) is the contrast ratio
\(L1\) is the relative luminance of the lighter color
\(L2\) is the relative luminance of the darker color

What is a Contrast Ratio?

The contrast ratio measures the difference between the brightest white and the blackest black that a display can produce. It is a critical specification for displays, such as televisions and computer monitors, as it directly affects the quality and clarity of the visual experience. A high contrast ratio is essential because it allows for better differentiation between dark and light areas on the screen. This means images and videos will appear more vibrant and realistic, with enhanced details and depth. A display with a low contrast ratio, on the other hand, may result in washed-out or dull visuals, where darker areas may appear gray or lack definition.

Example Calculation

Let's assume the following values:

Relative Luminance of the Lighter Color (L1) = 0.8
Relative Luminance of the Darker Color (L2) = 0.2

Using the formula:

\[ \text{cr} = \frac{0.8 + 0.05}{0.2 + 0.05} = \frac{0.85}{0.25} = 3.40 \]

The Contrast Ratio (cr) is 3.40.