Geng Gao | the Blog | design, software, gadgets topics... |

[Windows/Mac/Linux] Em Calculator is a very Useful Adobe AIR app for web designers. It's an easy to use em calculator and CSS generator on your desktop.

So What is an em?

An em is a relative typography measurement based on the square of the font size at that particular point. Originally the unit was derived from the width of the capital "M" in a particular typeface since the "M" was commonly cast the full-width of the square "blocks". But in modern typefaces, the character M is usually somewhat less than one em wide.

Use em in Web Typography?

If you ever wanted to convert px to em, Em Calculator is the tool for you.

The calculator defaults to a required base font-size of 12px and a 21px line-height. You can make adjustment.

The next step will generate CSS. Type style element name and click calculate initial size.

That's it. The CSS is generated. You can also make changes and re-calculate size it.

Also, you can add margins and paddings in unit of line-height.

You can either copy the CSS or make another CSS rule and copy them all.

Where to get this app?

You can get Em Calculator from James Whittaker' website

Further Readings

• How Big is an Em? About.com
• How to Size Text in CSS