When you are formatting text in your document, one of the things that you can specify is the font size of that text. Each character in your document can be a different font size, if you desire. You specify the size of font to use in points, a typographical measure that is roughly equivalent to 1/72 of an inch. Word supports font sizes from 1 point to 1638 points, which means you can use fonts that are 1/72 of an inch all the way up to 22-3/4 inches.

Don't these sizes deceive you, however. You might expect that if you set a font size to 144 points, you will end up with letters two inches high. You won't. What you really end up with actually depends on the font you selected. Font sizes are measured from the top of the ascenders on a letter (ascenders are the portions of a letter that point upwards) to the bottom of the descenders on a letter (descenders are the portions that point downwards).

This means that except in a few specialty fonts, no single character in the standard English alphabet will have the full height of the font, because no letter uses both ascenders and descenders. One way to see the full height of the font in one character is to use the Middle English thorn, a bizarre little character that looks like a combination lowercase b and p. You create the character by holding down the Alt key and pressing 0254 on the numeric keypad. Since the character has both a descender and an ascender, you can see the real size of the font.

The bottom line is that if you want to use very large font sizes and you want to make sure that your letters are a specific size, you will need to play around to figure out which font size is best for you. Pick a letter (perhaps a capital letter X) to be your "reference" letter, and then print some in various sizes. When you find the one that appears to be the size you want, you will then know what point size to make the rest of your characters.