Slide contrast checker

Check the colours of a slide the way a room will actually show them. Nothing to install, no account, and it runs entirely in your browser.

Put your deck's four colours in below. You get a readability verdict for each one, and when a colour falls short, the nearest colour that would pass. Not sure what to look at?

Your slide colours

Section label

A title at the size a slide actually uses

And body text underneath it, at the size an audience in the back row has to read from about twenty feet away.

Why three results and not one. WCAG treats anything from 18pt, or 14pt bold, as large text, and most slide type is bigger than that. So a slide usually only has to clear 3:1 to pass AA, which is a low bar in a room with the lights on. The third line is a practical recommendation for projection, not a standard: aim for AAA, 7:1 for body text, because ambient light and a tired projector bulb both eat contrast that a monitor never loses.

What the numbers mean

Contrast ratio runs from 1:1, identical colours, to 21:1, black on white. WCAG 2.1 AA asks for 4.5:1 on normal text and 3:1 on large text. AAA asks for 7:1 and 4.5:1. The calculation here is the WCAG relative luminance formula, unmodified.

Projection is not covered by WCAG, which was written for screens. There is no official projector standard, so nothing on this page claims to test against one. The AAA target is offered as a margin of safety, which is why it is labelled a recommendation.