How Do You Accurately Use an Online Ruler for Measurements?

Hey everyone,

I’m trying to take precise measurements for a project and came across several online ruler tools. I’m a bit confused about how to ensure accuracy, especially since screen sizes and resolutions vary. I’ve read that one way to improve precision is to use an online ruler that allows calibration based on your screen size.

Has anyone tried this successfully? Are there any reliable tools you’d recommend? Also, can they be used for both inches and centimeters accurately? I’d appreciate any tips, tools, or walkthroughs you’ve found helpful.

Thanks in advance!