Do Font Size and Colour Affect SEO?

Yes — the size and colour of the fonts you use can impact SEO!

There are two main reasons for this: readability and user experience

Readability is key 

Readability matters. At its core, SEO is about people. Search engines aim to deliver high-quality content to users, and if your website isn’t readable, it won’t rank well.

Here’s how to enhance your site’s readability:

  • Pick a sensible font size – not too big, not too small. Make sure your text can be read clearly across devices: PCs, tablets, and mobiles.
  • Pick a colour that goes with the background – opt for high-contrast colours. For example, dark text on a light background (or light text on a dark background) improves visibility for all users. This is especially important when designing for users with limited or impaired vision.
  • Make links look clickable – links should be easily recognisable. Blue is the universally understood standard for clickable text. Avoid making links the same colour as your regular text, as this can frustrate users and decrease engagement. A visitor is far less likely to browse the rest of your site if they struggle to discern your links! Frustrating your users needlessly is never a good idea.

Avoid deceptive practices

The second way font size and colour affect SEO is more technical: search engines penalise websites that appear to be engaged in deceptive practices, such as “hiding” text on a webpage.

Don’t try to hide text using colour or size

Making text the same colour as the background, using a font size so small it’s illegible, or hiding text with CSS tricks is a bad idea. The practice of inserting keywords into a webpage and “hiding” the text from users’ view is an old one, but it is completely ineffective for SEO purposes. What’s more, Google considers this manipulation, and your rankings will suffer.

However, it’s acceptable to “hide” text in certain situations. For instance, using toggles or buttons to reveal content, e.g. FAQ sections where a button causes the “hidden” FAQs to be revealed.

It’s also acceptable, as part of mobile-friendly design, to hide or reveal text based on screen size or device type using CSS @media rules. Google is aware of this and it will never impact your SEO negatively – on the contrary, designing your site to be mobile-friendly is one of the best moves you can make.

Mobile friendliness and accessibility matter

Google prioritises websites designed with accessibility in mind. Mobile-friendly, high-contrast text, and responsive fonts all contribute to ensuring a positive experience for your users.

Remember: Google uses a mobile-first approach. The mobile version of your website is what Google uses to determine ranking and indexing, so a poor, frustrating mobile experience must be avoided at all costs. Whether your visitors are using a phone, tablet, or desktop, your content should be easy to read and navigate.

Summary

In summary: pick high-contrast colours, with readable fonts of a sensible size that can be read clearly across devices, and never try to deceptively hide text from your users’ view.