Does font size impact SEO?

Yes, it does impact your SEO. In fact, a simple tweak to your theme’s settings page or your stylesheet has the potential to improve your website SEO, conversion and user experience in a way you didn’t imagine. Improving your font size is normally easy.

Font size on the internet

The internet is a different world from print and word processors world in many different ways, and fonts are no different. For that reason, it is vital to define the font size in web-specific terms. 

Unit of measurement

Font size on the internet and anywhere else are measured differently. Often, a font is measured in pt (points) and px (pixels). Font sizes can also be measured in the following ways:

• rem
• em
• percentages

Though pixels and points are the common units of measurement, they are not equal to each other and conversion is necessary when switching from either. Basically, 12 pt is equal to 16 px on most devices.

Percentages, em, and rem are relative font sizes (relative to the base font: 12 pt or 16 px) and are the preferred method in responsive web development, so there is a possibility your theme or design uses them. In theory, if set 100%, 1rem, or 1em, that is the same as selecting 12 pt or 16 px for most devices.

With these three font sizes, it is easier to defines lists, headers, and other elements relative to the body of your text. For instant, you can set your header to 1.5em or 150%, making them 50% bigger. 

If you want to increase the size of your entire site, you can do that by adjusting the font size on the root or body, and everything else will be adjusted. 

How does font size affect SEO and conversion?

Increasing font size for SEO and your readers

SEO and usability are closely related: a website that is user friendly will have a lower bounce rate, longer sessions and higher conversions. A good user experience will result in a longer dwell time (the time before a searcher returns back to the SERP. -Search Engine Result Page), which in turn affects your rankings.

The font size of your website isn't a ranking factor in itself - if only SEO was as easy as picking the right font size. But it is an important part of the usability of the site. A font size that is too small or too large annoys your users and hurts your SEO and conversion.

So, keep that in mind when choosing the right font sizes for your site. And considering now Google uses a mobile-first index to index web content today; you need to make sure your text can be read comfortably on mobile devices.

If too small, your readers will be forced to pinch and zoom to read. If too large, they will be forced to scroll a lot to complete reading. For that reason, it is good to stick to the right font sizes for the best user experience across all devices. 

Google’s Lighthouse tool helps you measure your website fonts to determine mobile-friendliness, which is something good when calculating your SEO score. Currently, this tool recommends 16 px as a base font of a site. This means the primary text of your font should be set to 16px or 12 pt minimum.

In fact, that is where Google’s Material Design style guide sets the base font size in its typography as well. So, for SEO, you require a minimum of a 16px or 12 pt font for your site to considered mobile-friendly, which is crucial in the mobile-first index.

Can you go even bigger than that?

Yes, you can. We have seen websites using large fonts performing extremely very well. The best thing with larger fonts is looking good and providing better user experience. 

Bonus! All themes and fonts will look different at different sizes.

If not sure what font size works best for you, feel free to experiment but remember that Google is happy with a 16px. 

Where do you make these changes?

There are several ways to go about this:

• If your theme has customization options, leverage them to adjust your font sizes.
• If it doesn’t, email the theme creator and you will be advised on how to adjust your font size.
• Adjust the font sizes yourself by editing your CSS file. See the example below: 

body {
font-size : 18px;
}
h1 {
font-size : 24px;
}

Since a lot is going into the theme besides the font size, such as character kerning, line heights, and fonts, we recommend you consult an expert if you find yourself in a dilemma. 

Readability beyond font sizes

If we're trying to make a text easy to read, there's more than just font sizes. The space between the lines (line-height), the space between paragraphs (margin) and the the space between headings and the paragraph below it all need to fit together to make a text readable.

Font size and relevance of text

You probably know that a H1 or H2 is considered more important than regular text on a website. Google has said that it's not just the type of heading, but also it's size that determines the relevance. The size of the text is used to understand the structure of the page. A large text will be considered more relevant than a small text, regardless of which heading type it is.

If you think of it, this makes sense: as a visitor, you also use large texts to scan the page and understand the hierarchy of the different elements. Google uses font sizes in much the same way.

Conclusion

Font size in itself is not a ranking factor, but selecting the right font size contributes to a better user experience. This in turn helps improve the SEO performance and the conversion of your website.

Secondly, select the right font size for different headings and subheadings to make the structure of a text clear to search engines and to your users.