About Ruler Now
Ruler Now is a ruler for your screen. It started from a simple annoyance: most "actual size" online rulers aren't actual size at all, because a web page isn't told how big a screen's pixels really are. This one tries harder. It recognizes common devices, makes a sensible estimate on the rest, and lets you make it exact in a minute with a bank card.
What's on the site
- A ruler in centimeters, millimeters and inches, and a pixel ruler.
- A protractor, a caliper and a multi-point tape.
- A ring size tool and a printable ruler.
- A unit converter for everyday lengths.
- A blog with practical guides, like finding your ring size or reading an inch ruler.
How we keep it accurate
The conversions use exact definitions (an inch is 25.4 mm by international agreement), and the measuring code is covered by automated tests. On-screen accuracy still depends on your screen, so we say plainly where the ruler is exact and where it's an estimate, and we don't recommend it for anything safety-critical. The disclaimer explains the limits.
Free to use
There's no account and nothing to install. Your settings stay in your own browser. The site may show advertising to cover its costs. See the privacy policy for what that involves.
Get in touch
Found a mistake, a device where the size is off, or a tool you'd like to see? Email contact@rulernow.com, or use the contact page.