Sunday, January 10, 2016

The Best Virtual Protractor and Ruler for Chrome

As we continue to move more into digital activities for our students, some things that often stay non-digital are physical manipulatives including rulers and protractors. Certainly there is nothing wrong with using wooden or plastic rulers and protractors (our students do need to know how to use them) but there are also benefits to having online alternatives:

  • They can’t be left at home, or at school, or broken
  • They are easy to turn on and off as needed
  • They work great with online activities and websites (no concern about scratching the screen)
  • Students can't hit each other with digital rulers
  • They are free!

Below you will find information about my favorite virtual ruler and favorite virtual protractor. Both of these require the Chrome web browser, but once you have them open they work on any website. You can watch the short video below to see them being demonstrated and/or read the rest of the blog post below for details.

Edge: The Web Ruler

My choice for the best virtual ruler is Edge: The Web Ruler. This tool is a Chrome Web App that can be installed from the Chrome Web Store at:

After installing the Web Ruler you can launch it from your Chrome apps screen. This will open up a virtual floating ruler on your screen

  • You can move the ruler around by simply clicking and dragging it.
  • You can make the ruler longer or shorter by dragging the end of the ruler.
  • You can switch between pixels (px), centimeters (cm), or inches (in) for your unit of measurement.
  • You can make the ruler more accurate by entering the diagonal measurement of your actual screen.
  • You can click the gear icon and choose “Always on top” to keep the ruler from falling behind your webpages.
  • You can open another copy of the ruler by clicking on the horizontal or vertical ruler icons.
  • When done using the ruler, click the “x” to close it out.

MB-Ruler for Chrome

My choice for the best virtual protractor is MB-Ruler for Chrome. This tool is a Chrome Web Extension that can be installed from the Chrome Web Store at:

After installing MB-Ruler you can launch it from your extension bar in the top right corn of Chrome. Then simply click on the protractor icon to open the virtual floating protractor.

  • You can drag the red dots on the edges of the protractor to rotate the protractor, as well as the change its size as needed.
  • You can drag the red dot at the center of the protractor to move it around the screen.
  • You can also drag the blue dot to drag out a reference line for a more accurate angle measurement.
  • When done using the protractor just click on the same protractor icon you used to open it.

Both of these virtual manipulatives can be very useful for instruction, practice, and inquiry in the classroom. Students can use them to measure and explore angles, as well as measure lengths in both inches and centimeters. This could be used with activities including Google Drawings (measuring shapes and angles), Google Maps (angles of street intersections), online photos (using proportions for indirect measurement), or any website. Best of all they are free, easy to use, and impossible to lose!

If you have a favorite tool for a different virtual ruler, protractor, or other measuring tool, please share in the comment below.

Also, if you found this information useful, you may also like some of my other technology ideas for math including:


  1. Thank you! I am going to add the app and extension to our district "approved" list in the admin panel now!

  2. Agree with @Pam-- will add for our teachers. Thanks!