Following up from my discussion of hard-to-read font sizes on iPhones, I bought a new pica rule and measured type sizes in points on an iPhone X. To do that I needed both my glasses and a loupe.
One could do all sorts of calculations to map pixels to points. None of that matters, because what you’re looking at has a definable point size, and that’s what I’m listing here.
| Setting | Point size | Cap height |
|---|---|---|
| [smallest] | 6⁻ pt. | 4 pt. |
| –10 | 6 pt. | 4⁺ pt. |
| –9 | 6 pt. | 4⅓ pt. |
| –8 | 6½ pt. | 4¾ pt. |
| –7 | 7¾ pt. | 6⁻ pt. |
| –6 | 8½ pt. | 6 pt. |
| –5 | 9 pt. | 7 pt. |
| –4 | 12 pt. | 8 pt. |
| –3 | 14 pt. | 11 pt. |
| –2 | 16 pt. | 13 pt. |
| –1 | 20 pt. | 15 pt. |
| [largest] | 26 pt. | 17 pt. |
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Point size means the distance from top of caps to bottom of descenders. (System typeface [San Francisco] obviates the need to compensate for ascender heights taller than cap heights because those two are the same.)
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⁻⧸⁺denote an unmeasurable fraction below or above an integer, though ostensibly that value could be estimated more closely if I bothered to map pixels to points. -
Bold vs. roman does not affect point size.