A screen ruler for everyday checks.

RulersKit is a browser-based ruler for checking lengths directly on your screen. Choose centimeters, millimeters, or inches, then use the workspace to compare an object or on-screen design with the scale.

Set the scale for your display

Browser pixels do not have one guaranteed physical size across displays. You can adjust the ruler against a standard bank card or enter a known physical length and match the on-screen reference to it. These methods create a scale from the reference you provide; the result depends on how closely the reference is matched.

RulersKit can also use a device-based display estimate when a supported model is selected or identified. Device estimates are not physically verified and may not match the screen's actual dimensions. Recalibrate after changing browser zoom, display scaling, or monitors.

What you can use it for

The ruler can help with quick layout checks, comparing visible objects, and estimating dimensions of items displayed on a screen. For physical work that needs a dependable measurement, use a physical measuring tool or calibrate against a known reference and confirm the result independently.

Measurements stay in the browser

Point selections and distance calculations are handled by the page in your browser. Calibration and display preferences are saved in your browser's local storage so they can be restored on a later visit.