Fonts are divided in proportional and monospace categories depending on how each font deals with the space between characters. Although both categories of fonts can be used for any type of text, both on the computer and in print, each category has pros and cons and works best for specific usages.
In a proportional font, such as the font this article is set in, different letters have different widths. For instance, the letter "I" is much narrower than the letter "W." Most books, magazines and other printed materials are set in proportional fonts; similarly, the graphical user interface of many programs uses a proportional font for titles, menus and other text. Examples of commonly-used proportional fonts are Times New Roman, Verdana, Arial, Georgia and Comic Sans.
Benefits and Disadvantages of Proportional Fonts
Text set in a proportional font is more visually appealing and often easier to read. Because of the variable spacing between characters, it can be easier to focus on each word as a whole rather than on individual characters.
On the other hand, proportional fonts present a disadvantage in some situations. If you want to be able to easily calculate the amount of characters present in a line of text, or identifying individual characters is of the foremost importance, using a proportional font will make your task harder. Additionally, in some proportional fonts some characters can be easily mistaken for others: for example, a lowercase "l" and a capital "I" or the number "0" and the capital letter "O" may look almost identical.
Each character in a monospace font, including punctuation, has exactly the same width. There is no width difference, for instance, between the letter "I" and the letter "W." Monospace fonts can be reminiscent of pages typed on manual typewriters. Some basic text editors such as Notepad for Windows use a monospace font to set text, as do some specialized editors used for programming in various languages. Examples of commonly-used monospace fonts are Courier New, Fixedsys, Monaco, Lucida Console and Andale Mono.
Benefits and Disadvantages of Monospace Fonts
Setting text in a monospace font makes it easier to identify characters by themselves. Because of this, tasks that rely on the easy identification of specific characters, such as programming, benefit from the use of a monospace font. Similarly, a monospace font may be used to format code examples within a page that is otherwise set in a proportional font, in order to make them stand out more easily. Text set in a monospace font is also easier to align, leading to the creation of images constructed using characters, known as "ASCII art."
On the other hand, because of the fixed width of all the characters, a block of text set in a monospace font will typically take up more space than the same text set in a proportional font. Additionally, long stretches of monospaced text can blend together visually and, as a result, become harder to read.