About RealLineal
A simple, accurate ruler right on your screen. Measure small objects in real life with true 1:1 scale — free, private, and instant.
Why We Built It
We have all been there: you need to measure a small screw, a coin, a ring, a credit card slot, or a craft piece, but there is no physical plastic ruler in sight.
Searching for a ruler online often gives inaccurate results. Because every screen has a different pixel density — a phone display packs far more pixels per inch than a desktop monitor — a standard picture of a ruler is rarely accurate to real life.
RealLineal fixes this problem. With easy calibration, one centimeter or one inch on your screen becomes exactly one centimeter or one inch in real life.
Simple Ways to Get True Size
Pick whichever method is easiest for you:
Check with Any Card
Every bank card, ID card, or transit card is standard size (85.6 mm). Hold your card to the screen, slide to match, and you are calibrated.
Pick Your Screen Size
Know your screen size? Click popular options like 13.3″, 14″, 15.6″, or 24″. The ruler instantly adjusts to your display.
CM, MM & Inches
Switch units anytime. Read clear metric ticks down to millimeters or fractional inches with an interactive guide line.
RealLineal runs entirely in your browser. There are no accounts to create, no software to install, and no tracking of what you measure. Your calibration is saved only on your device so it is ready whenever you return.