Rules for Using Periods
Periods are the marks that appear at the end of a complete sentence. They are considered to be full stops, rather than pauses.
Rules that apply to the use of periods:
- When a complete sentence is a statement, not a question or exclamation, use a period.
- A complete sentence has a subject and a predicate, or verb. It expresses a complete thought; therefore, the reader needs to know when to stop reading. A period indicates that a sentence has ended.
- Sometimes a sentence will have a word at the end that is an abbreviation ending in a period. When this happens, do not add another period at the end of the sentence. For example, "My uncle studied for years and finally earned his Ph.D."
- An indirect question is one where the writer states that someone asked something. The period is the appropriate ending for an indirect question. For example, "She asked what time it was."
Spacing after Periods
Software programs that use proportional spacing automatically add enough space after a period. Therefore, it is only necessary to hit the space bar once after typing a period. Some users are in the habit of hitting the space bar twice. This habit is left over from using a typewriter. Typewriters used manual spacing, meaning the space allotted for each letter was the same size. Many who learned to type on a typewriter were taught to hit the space bar twice after the period to create the correct amount of space. Doing this when using software programs such as Microsoft Word creates large blank spaces. Too many of the large blank spaces can cause what are called "rivers" in the body of the text. As the name suggests, the spaces cause the text to appear as if it there are clear paths winding through the text. From an aesthetic as well as space perspective, it is now correct to type only one space after a period at the end of a sentence.