Here's a literature review on the topic: https://www.researchgate.net/publication/234578707_Optimal_Line_Length_in_Reading--A_Literature_Review https://www.rese

Here's a literature review on the topic: https://www.researchgate.net/publication/234578707_Optimal_Line_Length_in_Reading--A_Literature_Review https://www.researchgate.net/publication/234578707_Optimal_L.... The article content is inaccessible, but from the abstract: > Research has led to recommendations that line length should not exceed about 70 characters per line. The reason behind this finding is that both very short and very long lines slow down reading by interrupting the normal pattern of eye movements and movements throughout the text. And a document on the topic from the US government: https://www.usability.gov/get-involved/blog/2006/08/line-length-and-onscreen-reading.html https://www.usability.gov/get-involved/blog/2006/08/line-len... > The best available research suggests that users will read fastest if the line lengths are longer (up to 10 inches). If the line lengths are too short (e.g., two and a half inch columns), the line length probably will impede rapid reading. Users tend to prefer lines that are relatively short (about four inches). Wikipedia cites a whole bunch of studies on the topic (https://en.wikipedia.org/wiki/Line_length https://en.wikipedia.org/wiki/Line_length): > Legibility research specific to digital text has shown that, like with printed text, line length can affect reading speed. If lines are too long it is difficult for the reader to quickly return to the start of the next line (saccade), whereas if lines are too short more scrolling or paging will be required. [...] One proposal advanced that, in order for on-screen text to have the best compromise between reading speed and comprehension, about 55 cpl should be used.[11] On the other hand, there have been studies indicating that digital text at 100 cpl can be read faster than text with lines of 25 characters, while retaining the same level of comprehension. There's a decent amount of variance, but common across all research in this area is that many hundreds of characters per line is never found to be the optimal length of a text column.