Define what smallest means in the actual task
A request for the smallest font can mean the least width, the lowest visible lowercase height, the fewest pages or the lowest readable setting. These are different comparisons. Write down which constraint matters before judging a sample. A face that appears smaller at one point size has not necessarily made the same information easier to read. For the measurement question, use the 12-point reference; for a scoped print recommendation, see the minimum-print guide.
Optical design can change the letters rather than only their scale
TypeTogether’s account of Atlante describes an optical axis that increases x-height and spacing and strengthens thin strokes and serifs for reduced sizes. Its Literata 3 account likewise distinguishes headline drawings from a caption direction with sturdier serifs and different spacing. These are documented design responses to scale, not claims that either family establishes a smallest universally readable size. An optical-size choice changes the design; simply reducing an unchanged display drawing does not do the same job.
Run separate equal-size and equal-appearance comparisons
Prepare the exact small paragraph, including numbers, punctuation and required accents. First compare Source Serif 4, Lora and Source Sans 3 below at the same nominal size and available width. Note apparent lowercase height, open spaces and line endings. Then adjust sizes until their visible scale is comparable and review how much space each passage occupies. Keep those two comparisons labelled separately. The specimens compare named styles; they do not provide a control for every optical axis or prove how an unavailable font edition behaves.
Choose the working layout and preserve enlargement
For print, proof the actual output process and material instead of judging a magnified screenshot. For web content, test the smallest supporting label alongside the surrounding controls, then enlarge the text and check for clipped wording. W3C’s Resize Text criterion addresses enlargement up to 200 percent without loss of content or functionality, with stated exceptions. That requirement is about usable resizing, not a universal minimum starting size. Shorten repetition or change the layout before sacrificing information merely to obtain a smaller page count.
Your questions, answered.
Which font is the smallest?
There is no single useful ranking without a constraint. Least width, lowest visible height and smallest readable setting measure different things and depend on the actual text and output.
Does optical size mean the same thing as font size?
No. The cited foundry accounts describe letterform and spacing adjustments for different intended scales. A numeric font size alone does not establish those changes.
Sources & background
Sources supporting this page’s explanations. Practical examples are our editorial suggestions.