Measurement Guides & Tips
Practical guides on measuring, unit conversion, screen calibration, and getting the most out of your online ruler.
How to Measure Your Ring Size at Home (Without a Jeweller)
A step-by-step guide to measuring your ring size accurately using a piece of paper, string, or an online ruler, no jewellery shop visit needed.
10 Things You Can Use to Measure When You Don't Have a Ruler
From credit cards to coins to A4 paper, everyday objects with known dimensions you can use as measurement references in a pinch.
Screen DPI Explained: Why Your Online Ruler May Be Wrong
A deep dive into pixels per inch, device pixel ratios, and why a CSS "inch" on your screen probably isn't a real inch, and how to fix it.
CM vs Inches: Which Unit Should You Use?
A practical guide to when to use centimeters versus inches, with country-by-country context and tips for working across both systems. Coming soon.
A4 vs Letter Paper: What's the Actual Difference?
A4 (210×297 mm) and US Letter (215.9×279.4 mm) look similar but differ in both width and height. Here's when it matters. Coming soon.
The Metric System in Everyday Life: A Practical Guide
From millimetres on a ruler to kilometres on a road sign, a practical guide to the metric system for those who grew up with inches. Coming soon.
Ready to measure something?
Head back to the free ruler tool, calibrate your screen and start measuring in CM, MM, or inches instantly.
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