Question 1

How accurate is the online ruler?

Accepted Answer

The accuracy depends on your screen DPI. Use the calibration feature by placing a real credit card or coin on screen and adjusting until the reference size matches.

Question 2

How do I calibrate the ruler?

Accepted Answer

Use a physical object with a known size (like a credit card which is 85.6mm wide). Drag the calibration bar edges until it matches the real object on your screen.

Question 3

Does this work on mobile?

Accepted Answer

Yes. The ruler works on any device. On mobile, rotate to landscape for a longer ruler.

Question 4

Can I switch between cm and inches?

Accepted Answer

Yes. Click the cm or inch buttons to toggle units. Both centimeters and inches are displayed.