The default indent in most software, depending on the program, is typically five spaces (1 tab), 1/4 of an inch, or 1 em (equivalent to the point size of the type). Don't use spaces or tabs to set paragraph indents. Use the paragraph formatting options offered by the software. Using the
em is usually the best way to specify indents. For example, a 1-em indent for 12 point type is 12 points while a 3-em indent for 10 point type is 30 points.
Ragged-right alignment usually requires deeper indents to create a clear demarcation between paragraphs.
With very deep indents, pay careful attention to the length of the last line of the preceding paragraph. If it is too short, it creates excess, distracting space. You may need to carefully adjust character spacing and line endings to avoid short lines followed by deep indents.
