Pixel Ruler
Drag to place a ruler on your screen. Measure widths and heights in pixels, centimetres, or inches — useful for UI design, screenshots, and front-end work.
How to Use Pixel Ruler Online
ToolsPix Pixel Ruler lets you drag a precise ruler anywhere on your screen to measure widths and heights in pixels, centimetres, or inches — all inside your browser, with no software to install and no data ever leaving your device.
Why use ToolsPix Pixel Ruler?
- Completely free with no sign-up or account required.
- Works entirely in your browser — nothing is uploaded or tracked.
- Supports pixels, centimetres, and inches with automatic DPI detection.
- Drag and resize the ruler, or switch between horizontal and vertical orientation.
- Crosshair overlay shows live X/Y coordinates as you move the mouse.
Steps to measure with the pixel ruler
Click and drag anywhere in the ruler area above to place the ruler. Drag the green handle at one end to resize it, and drag the ruler body to reposition it. Switch between px, cm, and in using the unit buttons, and toggle Horizontal or Vertical mode as needed. The stats bar shows width, height, and position in real time.
FAQ
How accurate is the pixel ruler?
Pixel measurements are exact — 1 CSS pixel = 1 screen pixel at 100% zoom. For centimetre and inch measurements, accuracy depends on DPI detection estimated from your screen's devicePixelRatio. On standard monitors this is very close; on HiDPI/Retina displays it may vary slightly.
What is DPI and why does it matter?
DPI (dots per inch) or PPI (pixels per inch) measures how many pixels fit in one inch of your screen. Standard monitors are around 96 dpi, while Retina displays can be 220+ dpi. Knowing DPI lets this tool convert pixel measurements into real-world centimetres and inches accurately.
Can I measure elements in another browser tab?
Not directly — browser security prevents cross-tab interaction. However, you can take a screenshot of the other tab, open it in this tab as an image, and then measure elements within that image using the ruler.
Does it work on touchscreens?
Yes. The ruler supports both mouse and touch input. On a touchscreen, use one finger to drag and place the ruler, then drag the handle at the edge to resize it.
Is the pixel ruler free and does it send my screen data anywhere?
The tool is completely free with no sign-up required. All measurements happen locally in your browser using JavaScript — no screen data, coordinates, or usage information is ever sent to any server.