einundzwanzig-verein/videos/.opencode/skills/remotion-best-practices/rules/measuring-text.md

---
name: measuring-text
description: Measuring text dimensions, fitting text to containers, and checking overflow
metadata:
  tags: measure, text, layout, dimensions, fitText, fillTextBox
---

# Measuring text in Remotion

## Prerequisites

Install @remotion/layout-utils if it is not already installed:

```bash
npx remotion add @remotion/layout-utils # If project uses npm
bunx remotion add @remotion/layout-utils # If project uses bun
yarn remotion add @remotion/layout-utils # If project uses yarn
pnpm exec remotion add @remotion/layout-utils # If project uses pnpm
```

## Measuring text dimensions

Use `measureText()` to calculate the width and height of text:

```tsx
import { measureText } from "@remotion/layout-utils";

const { width, height } = measureText({
  text: "Hello World",
  fontFamily: "Arial",
  fontSize: 32,
  fontWeight: "bold",
});
```

Results are cached - duplicate calls return the cached result.

## Fitting text to a width

Use `fitText()` to find the optimal font size for a container:

```tsx
import { fitText } from "@remotion/layout-utils";

const { fontSize } = fitText({
  text: "Hello World",
  withinWidth: 600,
  fontFamily: "Inter",
  fontWeight: "bold",
});

return (
  <div
    style={{
      fontSize: Math.min(fontSize, 80), // Cap at 80px
      fontFamily: "Inter",
      fontWeight: "bold",
    }}
  >
    Hello World
  </div>
);
```

## Checking text overflow

Use `fillTextBox()` to check if text exceeds a box:

```tsx
import { fillTextBox } from "@remotion/layout-utils";

const box = fillTextBox({ maxBoxWidth: 400, maxLines: 3 });

const words = ["Hello", "World", "This", "is", "a", "test"];
for (const word of words) {
  const { exceedsBox } = box.add({
    text: word + " ",
    fontFamily: "Arial",
    fontSize: 24,
  });
  if (exceedsBox) {
    // Text would overflow, handle accordingly
    break;
  }
}
```

## Best practices

**Load fonts first:** Only call measurement functions after fonts are loaded.

```tsx
import { loadFont } from "@remotion/google-fonts/Inter";

const { fontFamily, waitUntilDone } = loadFont("normal", {
  weights: ["400"],
  subsets: ["latin"],
});

waitUntilDone().then(() => {
  // Now safe to measure
  const { width } = measureText({
    text: "Hello",
    fontFamily,
    fontSize: 32,
  });
})
```

**Use validateFontIsLoaded:** Catch font loading issues early:

```tsx
measureText({
  text: "Hello",
  fontFamily: "MyCustomFont",
  fontSize: 32,
  validateFontIsLoaded: true, // Throws if font not loaded
});
```

**Match font properties:** Use the same properties for measurement and rendering:

```tsx
const fontStyle = {
  fontFamily: "Inter",
  fontSize: 32,
  fontWeight: "bold" as const,
  letterSpacing: "0.5px",
};

const { width } = measureText({
  text: "Hello",
  ...fontStyle,
});

return <div style={fontStyle}>Hello</div>;
```

**Avoid padding and border:** Use `outline` instead of `border` to prevent layout differences:

```tsx
<div style={{ outline: "2px solid red" }}>Text</div>
```