I’m having trouble matching font sizes between my iOS app and the design files I received. The designer gave me mockups created in design software, but when I implement the exact same font size values in my app, the text looks noticeably smaller than what’s shown in the designs.
For example, I’m setting up my text labels like this:
Even though both the design tools and iOS use point measurements, there’s still a clear size difference. The text in my app consistently renders smaller than expected. Has anyone else run into this issue? What’s the best way to make sure the font sizes match exactly between the design mockups and the final app?
Indeed, this issue can arise due to the differing ways design tools and iOS interpret font sizes. Design software typically uses a font’s nominal size, while iOS focuses on the rendered height, which can differ between fonts. This can be especially problematic with custom fonts as their internal metrics may not align with iOS standards. When you specify 16pt, iOS applies the font’s built-in measurements, which could diverge from those used in the design tool. A practical approach is to measure the actual text height using NSString’s boundingRectWithSize method and adjust accordingly to find the right font size. It requires some trial and error, but once you determine the scaling factor for your custom font, you can apply it consistently. Additionally, verify you are using the exact font file provided by your designer, as even slight variations in font versions can lead to different rendering results.
for sure, that happens! maybe because of device scaling. try increasing the font size by like 20% or something - it could help. and yeah, make sure the font weights match up too, that can affect how it looks!
Yeah, this drives me nuts too. It’s usually DPI differences between your design tools and how iOS actually renders things.
Design software assumes 72 DPI, but iOS devices have all different pixel densities. Plus design tools can’t replicate iOS’s text rendering engine.
I got sick of manually tweaking font sizes for every project, so I automated it. Built a workflow that grabs design specs, calculates the right iOS scaling ratios, and updates my app’s font configs automatically.
It pulls font data from design files, compares against iOS standards, then pushes the fixed values straight to my dev environment. No more guessing.
I also added automated visual regression testing - takes screenshots of my app vs design mockups and flags any font mismatches right away.
Saves me hours per project and stops all the back-and-forth with designers about font sizing.
Had this exact problem on my last three projects. Design tools handle font baseline and leading differently than iOS does. Designers usually work with tight line spacing in mockups, but iOS adds default spacing that makes fonts look compressed. I created a simple comparison view in Xcode where I overlaid design screenshots directly onto my app interface. Let me spot differences fast and adjust font sizes in real time. Bumping font size up 1-2 points usually gets you close, but you also need to adjust line height with NSParagraphStyle. Your custom font probably has different ascender and descender values than the designer expects - that throws off visual weight even when point size matches.