Use periods in sentences that make statements.
- My dog retrieves the paper for me each morning.
- Gloria wants to be a nurse after she finishes high school.
- Our city’s police cars are painted black and white.
You should also use periods at the end of sentences that are intended to instruct or command.
- Rinse the dishes before putting them in the dishwasher.
- Lock the door behind you.
- Place recyclable items in the blue bin next to the dumpster.
Periods can also be used at the end of a sentence that contains an indirect question.
- The coach asked Jared why he was late for practice.
- My mother used to wonder why my brother’s room was cluttered.
- I have something to ask you.
How to Use Periods
After ending a sentence with a period, insert a single space before beginning the next sentence. This rule has only been in place since modern word processing became common – back in the days when people used typewriters, one would insert two spaces behind periods and other punctuation marks that end sentences.
Periods are also used with abbreviations.
- Washington, D.C.
- 5 p.m.
In the event that the abbreviation ends a statement, a command, or an indirect question, the period that ends that abbreviation is also used to complete the sentence.
- If you want to visit the Smithsonian Institute’s National Museum of American History, you will need to travel to Washington, D.C.
- Arrive at 5:30 p.m. to get a seat for the concert; it begins at 6 p.m.
Although acronyms are abbreviations, they do not normally require periods. If you are using an acronym that is pronounced as a word such as NOW, NATO, RADAR, or SCUBA, you don’t need to insert periods between the letters. If you are using an acronym that is pronounced by speaking the letters individually, you may or may not need to use periods between the letters. Some examples include FBI, NBA, NCAA, NAACP, U.S.A., and U.N.I.C.E.F.