Contrast Ratio Checker

Contrast Ratio = N/A
WCAG Standard	Small Text	Paragraphs User Interface Elements Visual Elements
AA	N/A	N/A
AAA	N/A	N/A

The optimal contrast score is 21, which occurs with white text on a black background.
To meet WCAG Standards, a minimum contrast ratio of 4.5 is required for small text and 3 for large text.

To calculate the contrast ratio between two colors, we use the following formula:

Contrast Ratio = (L1 + 0.05) / (L2 + 0.05)

where:

L1 is the luminance of the lighter color.
L2 is the luminance of the darker color.

For #FFFFFF (white):

R = 255, G = 255, B = 255
The linear values for R, G, and B are all equal to 1.
Relative luminance of #FFFFFF is: L#FFFFFF = 0.2126 × 1 + 0.7152 × 1 + 0.0722 × 1 = 1

For #000000 (black):

R = 0, G = 0, B = 0
The linear values for R, G, and B are all equal to 0.
Relative luminance of #000000 is: L#000000 = 0.2126 × 0 + 0.7152 × 0 + 0.0722 × 0 = 0

Now, using these relative luminances in the contrast ratio formula, we have:
Contrast Ratio = (L1 + 0.05) / (L2 + 0.05)
where:

L1 = 1 (luminance of white)
L2 = 0 (luminance of black)

Substituting the values:
Contrast Ratio = (1 + 0.05) / (0 + 0.05) = 1.05 / 0.05 = 21
Thus, the contrast ratio between white (#FFFFFF) and black (#000000) is 21.

WCAG Contrast Ratio Checker