RN & Flutter tools
// RN & Flutter

Responsive Font

> Scale typography from a design width to any device width — with optional min/max clamps.

scale.cfg

Scaled size

18.35

output.out
iPhone SE          375px → 16
iPhone 14          390px → 16.64
iPhone 14 Pro Max  430px → 18.35
Pixel 7            412px → 17.58
Tablet             768px → 24

// React Native
const scale = (size: number) =>
  (size * 430) / 375;

const fontSize = Math.min(24, Math.max(12, scale(16)));
// => 18.35

// Flutter
double scaleFont(double size, double screenWidth) {
  final scaled = size * screenWidth / 375;
  return scaled.clamp(12, 24);
}

// scaleFont(16, 430) => 18.35