# Caliper

> A measuring cursor overlay for design-spec pages that hides the system pointer and draws live crosshairs, hover outlines with size readouts, red spacing lines to the parent frame, and drag-to-measure or click-to-pin distance lines, with shift-to-snap to a grid.

- Author: [ham7a311](https://21st.dev/@ham7a311)
- Library: ham7a311
- License: MIT
- Tags: Cursor, Crosshair
- Live preview: https://21st.dev/@ham7a311/components/caliper

## Install

```bash
npx shadcn@latest add "https://21st.dev/r/ham7a311/caliper?api_key=$API_KEY_21ST"
```

Requires a 21st API key (generate one at https://21st.dev/mcp) passed as `API_KEY_21ST`. Free accounts get a limited number of installs per day; unlimited on a paid plan — see https://21st.dev/pricing.

Full component directory: https://21st.dev/llms.txt · More like this: https://21st.dev/community/components/s/cursor.md