Similar to the affect of font type, font size has a lot to do with how easily your information will be found, read and understood. Have you EVER found it easy to read the "fine print" of your credit card contract, auto bill of sale or other legally-binding document? Of course not, such is the result of font that is too small.

Remember that two of our goals when designing technical communication are making information easy to find, and making it easy to understand. Depending on what context your information is being transmitted, certain font sizes are better to use than others.

When writing information to be read on printed, paper documents, the smallest size you want to use for large amounts of text is 12 point. Studies have shown that this size allows the eye to quickly distinguish different words while at the same time allowing us to put an efficient amount of text on a page (81/2 X 11 U.S. letter size).

As a rule, start with 12 point and then move up 2 points for every heading level starting with the smallest. Thus, if you have two heading levels, the body would be 12 points (as it always should be), the largest heading is 16, the sublevel heading is 14 (figure 1).

Figure 1. Increase in font size from the smallest (10 point, for use with occasional textual elements) and increasing by 2 points.

Notice also the smallest font example used in figure 1: 10 point. This size is useful for "other" text elements used on the page, such as figure titles and table captions.

If font larger than 12 point is used, it may look odd or unprofessional (that's just not what our eyes are used to). And if it's too large, such as 16 or 18, and used for a large amount of text, it makes the information too difficult to read.

Keep in mind, as always, your audience. On the internet, users can increase the size of the font on their pages if they need to. However, this isn't possible on hard copy documents. Thus, if your readers have difficulty reading smaller fonts, ensure that that you have used the appropriate size to compensate for this difficulty: it is only ethical to do so.

Lastly, writing for the internet is different. First of all, as pointed out above, readers have the ability to choose the size of font most appropriate for them. However, with this in mind you still must use different sized fonts for different elements. Headings and sub-headings should be different sizes than body or content (just like the pages on this site).

Following these tips will create a better, more easily accessed information unit.

For technical, professional and business communication help in the Las Cruces, NM area, visit Lanier Infomedia. 

Last update: 27-03-2009 13:46