About This Launch
Online Ruler is a free set of measuring tools that run entirely in your browser. Its actual-size screen ruler shows centimeter, millimeter and inch scales, and a calibration step (match a bank card or enter your screen diagonal) fixes the usual problem of on-screen rulers being wrong on phones and high-DPI displays. An image measurement tool reads lengths from a photo, and a converter handles mm, cm, m, inches, feet and pixels. No account; nothing is uploaded.
Why I Built This
Most online rulers are the wrong size on modern screens. We built a calibrated ruler so anyone without a physical ruler can measure accurately.
Launch Details
CategoryProductivity
StageLive
ListedOctober 14, 2026