changing font size in Wordpress.com

Sadly, this isn't possible without really playing with html.  According to http://en.support.wordpress.com/editors/font-size-color/

You can change fonts using HTML but it’s fiddly and maybe not worth the hassle all the time but keep reading :)

To make the font changes shown above, the following code was added to the HTML editor:

<span style=”font-family:comic sans ms;font-size:x-large;”>You can change fonts using HTML</span> <span style=”font-size:x-small;”>but it’s fiddly</span> <span style=”font-family:georgia;color:#2233ff;”> and maybe not worth the hassle all the time</span> <span style=”font-family:arial;color:#ff00ff;font-size:xx-small;”>but keep reading :)</span>

So when you want to write differently you have 3 elements to play with: font-family, font-size, and color.

1. font-family – the style of type. Here is one site with examples: http://typetester.maratz.com
2. font-size – experiment with different sizes. See examples above.
3. color – use a hex code for the best range. Here is one site with colors:http://www.visibone.com/colorlab/big.html

Additional Information

• When you write HTML, you must make sure the code is well-formed. For example, every <span> tag must have a </span> tag.

• Make sure you are using regular quotes (” “) and not smart quotes (” “).

• Alternatively, you can change some aspects of the fonts using the visual editor icons including headings, paragraphs, indentation, alignment, and color.

• To change fonts globally, you would need to purchase the Custom CSS upgrade and have some knowledge of CSS in order to make the desired changes. If you’re new to CSS, there are some wonderfully helpful people to be found in the CSS Customization forum who may be able to help you out.

• We cannot alter a theme to accommodate your choice of font size. Please bear in mind that if we alter a theme for you then that alters the same theme for everyone else. They probably won’t like that happening.

To take the message above apart:

• You can change fonts using HTML = 
• <span style=”font-family:comic sans ms;font-size:x-large;”>You can change fonts using HTML</span>
• but it’s fiddly = 
• <span style=”font-size:x-small;”>but it’s fiddly</span>
• and maybe not worth the hassle all the time = 
• <span style=”font-family:georgia;color:#2233ff;”> and maybe not worth the hassle all the time</span>
• but keep reading :) = 
• <span style=”font-family:arial;color:#ff00ff;font-size:xx-small;”>but keep reading :)</span>

So if you're not interested in adjusting the color, the simplest html code to change the font size would simply be 

• <span style=”font-family:comic sans ms;font-size:x-large;”>You can change fonts using HTML</span>

where x-large is the size font you want.