Webopedia.com defines pitch as "the number of characters printed per inch." A fixed-pitch font is one wherein every character is the same width and thereby occupies the same amount of space on a page. A proportional font, or variable font, is one wherein the widths vary depending on the character's shape and, therefore, do not occupy the same amount of space on a page. The font used when creating a document will have different widths depending on their size.
Font is a design for a set of characters in print such as Times New Roman, Arial, Helvetica, Georgia and Century Gothic, to name a few. Fonts are characterized by size, spacing and pitch. Fonts can also be bold, italicized, underlined and upper case of lower case, among others. Additionally, the color of fonts and how they are positioned (vertically or horizontally) in a document can be changed.
Point Vs. Pitch
"Points" is the term used to refer to the height of characters in a chosen font. Each character is measured in points, which is about 1/72-inch point per font. "Pitch" which common values are 10 and 12, is the term used to measure the width of a character. In other words, it refers to the amount of characters that can fit in an inch horizontally.
The Concept of Pitch
Pitch only applies to fixed fonts, such as Courier New, and not to proportional fonts, such as Times or Arial. The amount of space occupied in fixed fonts being the same is most noticeable when comparing the letters "I" and "w" or "m." The characters in proportional-pitch fonts have different widths depending on their size so they have no pitch value. This is most noticeable when comparing the letters "d" and "l," wherein the letter "d" is noticeably wider.
12-Pitch Font Explained
Since pitch has to do with the width of a character, it determines the amount of space that is present between each character. A document that is printed at 12-pitch font, for example, will have more spaces between characters than the same document printed at 13-pitch font. Additionally, a document printed at 12-pitch font will take up more pages than the same document using the same characters printed using 13-pitch font.
Choosing a Font and Pitch
Adding too much space between a proportional font reduces the appearance of its presentation in comparison to the use of normal spacing. The size and pitch of the font must be considered when choosing a font and pitch. A larger font printed at a lower pitch may produce a set of words that is printed too close together. Likewise, selecting a smaller font printed on a larger pitch will add too much space between words. This makes the document not only unpleasant to view, but difficult to read as well, which makes choosing the right font and pitch important.