Our expert team at Squee conducts a thorough evaluation to pinpoint how your site can perform better.
Free accessibility tool
Check any two colours against WCAG AA and AAA. If the pair falls short, we give you the nearest colours that pass. Everything runs in your browser and nothing is stored.
This tool needs JavaScript to calculate contrast ratios. Email hello@squee.design and we will check your colours for you.
21.00:1
We do not recognise that text colour. Try a hex value like #1A1A1A.
We do not recognise that background colour. Try a hex value like #FFFFFF.
Your colours
A headline at full size
This is body copy at a normal reading size. If you have to lean in to read this comfortably, your visitors will have the same problem, and some of them will leave rather than squint. Here is a link inside a sentence for good measure.
Small print, captions and disclaimers sit around this size. They are held to exactly the same standard as body copy.
The quick reference
The threshold changes depending on what you are styling. Find the thing you are working on and read across.
This covers the contrast criteria in WCAG 2.2, which are a subset of the full AA standard. Clearing every row here does not make a page compliant on its own.
Your colours are sorted. A page can pass every ratio on this tool and still be unusable with a keyboard, or unreadable to a screen reader. Pop in your details and we will run a free automated check across the wider WCAG criteria.
The scan takes under a minute. Your scorecard appears on the next screen.
This usually takes 20 to 30 seconds. Hang tight.
Here to help you
No. Contrast is one success criterion out of dozens. A page can clear every ratio on this tool and still be impossible to use with a keyboard, unreadable to a screen reader, or confusing to navigate. Contrast is simply the easiest failure to find and the cheapest to fix, which is why it gets so much attention.
This tool compares two flat colours, so it cannot read a background that changes behind the letters. Sample the lightest and the darkest point of the image where the text sits, and test your text colour against both. If either fails, the text fails. In practice you are usually better off adding a solid panel or a scrim behind the text rather than trying to find a colour that survives the whole image.
Usually not. The requirement applies to a colour pairing, not to a colour on its own, so the same brand colour can be fine on one background and fail on another. Keep it for large headings, buttons and graphics where the threshold is lower, and use a darker or lighter variant for body copy. The suggestions in the tool hold the hue and only move the lightness, so what you get back still reads as your brand.
24px and above at a normal weight, or 18.66px and above when bold. That is the point where WCAG drops the requirement from 4.5:1 to 3:1. It is worth measuring rather than assuming, because a heading that looks large in a design often lands under the threshold once it is built and scaled down for mobile.
AA is the working standard and the one nearly every organisation is measured against, including under the Public Sector Bodies Accessibility Regulations. AAA is the enhanced level and is not expected across a whole site. It is worth targeting on long reading passages and on services an older audience depends on.
A separate rule covers the parts of an interface that are not text: input borders, meaningful icons, focus indicators and the lines on a chart. These need 3:1 against what sits next to them. Very pale grey form borders are the most common failure we see, and they matter more than they look, because they are what tells someone where to type.
More on accessible design
In July 2026, we assessed 50 Gloucestershire websites for accessibility: 24 charities and community groups, and 26 of the county’s largest organisations.
When Tim Berners-Lee created the World Wide Web, universality was one of its founding ideas. As he put it, “The...
What “Accessibility Standards” Actually Refer To When people talk about web accessibility standards, they are often using one phrase to...
We use essential cookies to make this site work. We would also like to set optional cookies that tell us how the site is used, so we know what is helping and what needs improving. We will not set optional cookies unless you turn them on, and you can change your mind at any time. Read our privacy policy.
Choose which cookies you are happy for us to use. Your choice is saved for six months, and you can come back and change it whenever you like using the Cookie preferences link in the footer.
These keep the site secure and remember your cookie choice. The site cannot work properly without them, so they are always on.
Always active
These tell us which pages people visit and how they move around the site, so we know what is useful and what needs improving. We use Google Analytics for this.
These let us show you our newsletter and offer prompts, and measure how many people get in touch after seeing our advertising. Turning these off means you will not see our popups.
