CSS line-clamp (and its prefixed version -webkit-line-clamp) is a CSS property that limits the number of lines displayed in a block container. When the text exceeds the specified line count, it is truncated and an ellipsis (…) is appended. It works together with display: -webkit-box and -webkit-box-orient: vertical to create a flexbox-based clamping effect. This is the cleanest and most widely supported method for multi-line text truncation.

The -webkit-line-clamp property is supported in all major browsers: Chrome, Edge, Safari, Opera, and Firefox (version 68+). As of 2024, the unprefixed line-clamp is supported in Chrome 120+, Edge 120+, Firefox 121+, and Safari 17+. For older browsers, a max-height fallback approach (combining max-height, overflow: hidden, and calculated line heights) can be used. Our tool generates both schemes so you can choose based on your target audience.

Line-clamp automatically calculates the truncation point based on actual line count, works with any font size and line height, and always appends an ellipsis (…) at the exact truncation point. Max-height fallback uses a calculated pixel value (line-height × number of lines) to set a maximum height, with overflow: hidden. However, it doesn't add an ellipsis automatically (you'd need text-overflow: ellipsis which only works for single-line), and it may cut text mid-line if the calculation is imprecise. Line-clamp is the recommended approach for modern projects.

To add a "Read More" button, place it outside the clamped container. Use JavaScript to detect if the content is overflowing: compare element.scrollHeight with element.clientHeight. If scrollHeight is greater, the text is truncated — show the "Read More" button. On click, remove the line-clamp styles (or toggle a class) to expand the content. You can also toggle back to "Show Less." Our preview demonstrates this interaction — enable the "Read More Button" toggle and resize the preview to see it in action.

The -webkit-line-clamp property always uses the default ellipsis character (…). To use a custom string, you can employ a pseudo-element technique: overlay a ::after element with your custom text (like "…more") positioned at the bottom-right of the container. However, this approach is more complex and may require hiding the last few characters using a gradient or background mask. For most use cases, the default ellipsis is recommended for its simplicity and reliability.

Common reasons include: 1) Missing display: -webkit-box and -webkit-box-orient: vertical — these are required for line-clamp to work. 2) The container is wide enough that the text fits within the specified line count. 3) The overflow: hidden property is missing. 4) The element has a fixed height that overrides the clamping. Always ensure you include all three required properties. Our generated CSS includes the complete rule set to avoid these issues.

No — line-clamp is purely a visual CSS property. The full text remains in the DOM and is accessible to screen readers and search engine crawlers. Unlike JavaScript-based truncation (which may physically remove text from the DOM), CSS line-clamp only affects the visual rendering. This makes it an excellent choice for SEO-friendly text truncation. Screen readers will still announce the full content, so consider adding an aria-label or using the "Read More" pattern for better accessibility if the truncated content is critical.