One‑Click Sketch Plugin to Match iOS Text Line Height

Many designers wonder why the line height in design drafts doesn't match the iOS system rendering. A common rule of thumb is line‑height = font‑size + 4, but this is not always correct.

To investigate, the author measured the default line heights of iOS for font sizes 10 px–28 px and compared them with the default line heights set in Sketch.

iOS line‑height rules discovered:

Font size 10 px → line height = font size + 2

Font size 11 px–20 px → line height = font size + 4

Font size 21 px–28 px → line height = font size + 6

Manually adjusting line height in design files can be tedious. The author introduces a Sketch plugin that automatically sets the line height of selected text layers to match iOS defaults.

After applying the plugin, the line‑height preview matches the iOS rendering (example with 14 px PingFang font). The default Sketch line height differs by a few pixels, which is noticeable to pixel‑perfect designers.

Plugin download: https://github.com/youngxkk/AutoFixiOSTextLineHeight

Usage steps:

Select one or multiple text layers or artboards.

Run Plugins → Auto Fix iOS Text Line Height → Fix or press ⌘ + Option + Shift + I.

The plugin works only for iOS text line height (tested with PingFang). Android has a similar but unstable plugin, which is not covered here.

Images illustrate the comparison before and after applying the plugin.