SpeedTest is an HTML5 app that lets you test websites at a variety of resolutions very quickly.

It also works on mobile, which allows you to test websites at a variety of widths on a phone or tablet where you can't normally change the width of the browser.

Just enter the URL of the page you'd like to test in the input field and select 'Go' or hit the enter key. Then you can manually resize the preview below by clicking and dragging the bottom right corner to any size you wish, or by jumping to predefined widths by pressing the 1–9 and ∞ buttons at the top of the screen, or pressing number keys 1–0 on the keyboard to jump to the predefined widths.

Pressing enter will refresh the page

You can also add the urL you wish to test to the URL after a ?, for example to load tomhodgins.com you could add ?http://tomhodgins.com to the end of the URL where SpeedTest is hosted.

• Demo: staticresource.com/speedtest.html

• Demo that loads tomhodgins.com: staticresource.com/speedtest.html?http://tomhodgins.com