react-native-text-measure

Accurately measure text width, height, and lineCount using native layout engines — no view rendered.

| Platform | Engine | Accuracy | |----------|--------|----------| | iOS | NSLayoutManager (TextKit) | ✅ Identical to UILabel | | Android | StaticLayout | ✅ Identical to TextView |

Installation

npm install react-native-text-measure
# or
yarn add react-native-text-measure

iOS

cd ios && pod install

Android

Auto-linking handles it on RN >= 0.60. For manual linking see android/README.md.

Usage

import { measureText, measureTextSync } from 'react-native-text-measure';

// ── Async (recommended) ───────────────────────────────────────────────────────
const { width, height, lineCount } = await measureText('Hello world', {
  fontSize: 20,
  fontFamily: 'Helvetica',
  fontWeight: 'normal',
  maxWidth: 300,
});

// ── Sync (use sparingly — blocks JS thread) ───────────────────────────────────
const result = measureTextSync('Hello', { fontSize: 16 });

API

measureText(text, options) → Promise<Result>

measureTextSync(text, options) → Result

Options

| Option | Type | Default | Description | |--------|------|---------|-------------| | fontSize | number | 14 | Font size in dp/pt | | fontFamily | string | system | Font family name | | fontWeight | string | 'normal' | 'normal', 'bold', '100'–'900' | | fontStyle | string | 'normal' | 'normal' or 'italic' | | letterSpacing | number | 0 | Extra letter spacing in dp/pt | | lineHeight | number | 0 | Explicit line height. 0 = natural | | maxWidth | number | 0 | Wrap width. 0 = no wrap (single line) | | maxHeight | number | 0 | Clamp returned height. 0 = unclamped | | numberOfLines | number | 0 | Max lines. 0 = unlimited | | includeFontPadding | boolean | true | Android only. Match your <Text> setting |

Result

{
  width: number;     // dp (Android) / pt (iOS)
  height: number;    // dp (Android) / pt (iOS)
  lineCount: number;
}

Accuracy notes

• Results are not estimates — both engines perform a full layout pass.
• letterSpacing unit differs between platforms (see inline comments).
• includeFontPadding must match your <Text> component on Android.
• If fontFamily is not found, the system font is used silently — measurement will be accurate but for the wrong font.

License

MIT