Online Ruler shows lengths on a screen. Accuracy depends on your device, browser zoom, operating system scaling and how carefully you calibrate.
- Readings marked Estimated are a guess based on your screen and can be off by several millimeters.
- Readings marked Calibrated are usually within about half a millimeter on the screen you calibrated, if zoom has not changed since.
- Device list values come from public specifications and may not match every version of a device.
Do not use the tools for medical, legal, engineering, safety or other uses where an exact measurement is required. For those, use a physical ruler, caliper or tape measure.
Product names in the device list belong to their owners and are used only to identify screens.