Both Raptive and Mediavine are now recommending publishers increase their font size to 20-22px and decrease the content width to 728px in order to boost RPMs.

While we can make this change to your site, it will have a noticeable impact on the visual design. We try to find a balance between maximizing RPMs and the reader’s experience on your website.

Here’s Duane’s opinion on the matter:

Some visual design feedback on this subject:

All of the above means that most of the text that most users see on their devices is in the 16-17 range. Deviating drastically from that range violates Jakob’s Law (Laws of UX).

We default our themes to 18, and in some cases have bumped to 19 or 20, but any larger than that and the number of characters per line falls below accepted readability standards. The issue is further magnified on mobile. At 18 we end up with 39 characters per line, which is uncomfortably tight, however at 22 we drop to just 32 characters.

Increasing the default to 22 is a poor decision. The resulting sites will be objectively less attractive, be harder to read, and most importantly will violate a critical Law of UX. I understand the competitive RPM implications, but this is a terrible way to try and boost that metric. It’s hostile design.

Respectfully, I cannot in good conscience recommend a body font size of 22 to our clients, and we definitely will not increase our default to that size. If a client requests it—which they absolutely will based solely on their ad provider’s recommendation without any understanding of readability or UX—I will first educate and advise them on why they should not, but if they insist we will of course do so!