This website provides free colour contrast analysis tools that will display the color contrast issues of a web page or chosen colour-pair; per WCAG 2.1 Guidelines. Color Contrast refers to how bright or dark colours appear against each other on screens; particularly with regard to the relative, grey-scale luminosity as perceived by the human eye.
When it comes to website accessibility, the contrast between the text and the text background is a concern for colour-blind and other visually impaired users.
This colour contrast tool enables users to comply with website accessibilities regulations.
WCAG Contrast Information
A minimum contrast ratio of 4.5:1 is required for the visual presentation of both text, and images embedded as text, against the presented background colour.
Large text (18pt+ or bold & 14pt+) only requires a 3:1 or greater contrast ratio.