Color contrast checkers gave me totally different results - which one do you trust?

I spent about 3 hours last week trying to pick a green for a button on a dashboard design. Ran it through three different free contrast checkers online and got three different ratios. One said it passed WCAG AA, another said it barely failed. Had to dig up the official WCAG formula myself and do the math by hand. Took forever. Anyone else run into this where the tools disagree? Which checker do you lean on?

2 comments

2 Comments

zara_allen9d ago

Tbh the math is the same if both tools are using the official WCAG formula, so the problem is usually just how they handle color profiles or rounding. If one tool says pass and another says fail by like 0.1, that's basically a rounding error and you should go with the fail to be safe. Pick the most conservative checker and stick with it forever, that's what I do.

rose_murray9d ago

Yeah I did the exact same thing with a blue link color a few months back. Ended up just using WebAIM's tool since it's from the actual WCAG people and it's never let me down.