What Are Periods (.) And How Do You Use Them?

You might have trouble reading these sentences they are all mashed together it is pretty confusing—stop! Now that we’ve caught our breath, we can see that something is missing from what could be three different sentences. These three sentences need to stop for a moment and learn about punctuation.

Punctuation is the system of marks, symbols, and characters that we use to make writing more clear and easier to read. In particular, our troublesome sentences are missing a period. The period is definitely a punctuation mark that we simply cannot do without.

What is a period?

A period is a punctuation mark that is used to end sentences. The period resembles a point or dot placed at the bottom of a line (.). The period has two major uses in English. Firstly and most commonly, a period is used to end a declarative sentence. Secondly, periods are often used in abbreviations.

When do you use a period?

As mentioned earlier, a period has two especially common uses. Let’s look at each of them more closely.

Ending sentences

The most common use of periods is to end sentences. When used this way, the period is placed immediately after the last letter of the final word of a sentence. Usually, a new sentence following a period begins with a capital letter:

• It is snowing outside. We are going to build a snowman. 

📝Most style guides and grammar resources advise using a single space after a period to begin a new sentence. In the past, it was common to use two spaces instead, so don’t be surprised if someone prefers the double space approach.   

A period is used inside of quotation marks when a quote comes at the end of a sentence:

✅ Correct: She said, “The concert is on Friday.”
❌ Incorrect: She said, “The concert is on Friday”.

In general, a period is used inside parentheses if they contain a complete sentence. Otherwise, a period follows parentheses that only provide additional information:

• Inside: I love cherry pie. (It is the best kind of pie.)
• Outside: I love cherry pie (the best kind of pie).

Periods are used to end declarative sentences. A declarative sentence is simply a sentence that gives a statement. Questions and exclamations are not declarative sentences and typically don’t end in periods. For example,

• Declarative sentence: Grass is green. (ends in a period)
• Question: Is grass green? (does not end in a period)
• Exclamation: This grass is blue! (does not end in a period)

An imperative sentence may use either a period or an exclamation point depending on what emotion someone is expressing. For example,

• Get me a fire extinguisher. (The speaker is making a simple request.)
• Get me a fire extinguisher! (The speaker is making an emotional or urgent request.)

Interjections often express strong emotions, so they may use an exclamation point instead of a period:

• Wow! That was an amazing performance.

However, a person may use a period with an interjection if they want to express a less excited emotion:

• Was the book interesting? Meh. I’ve read better.

Learn about the different sentence structures you can end with a period.

Abbreviations

Many abbreviations use periods. For example,

• The title of Doctor is abbreviated as Dr.
• Main Street is abbreviated as Main St.
• The title of Lieutenant colonel is abbreviated as Lt. Col.

However, there are several exceptions to this general rule:

• Often, mathematical or scientific abbreviations don’t use periods. For example, kilograms is usually abbreviated as kg with no period and the element sodium is abbreviated as Na without a period.
• Many abbreviations and acronyms that only use capital letters don’t use periods. For example, Pennsylvania is abbreviated as PA, United Kingdom is abbreviated to UK, and Central Intelligence Agency is abbreviated to CIA. Not all abbreviations follow this rule, though. For example, United States of America is often abbreviated as U.S.A. or U.S.

If you are unsure how to abbreviate a particular word, it is often best to consult your preferred style guide or dictionary.

If a sentence ends in an abbreviation, you only need a single period to complete both the abbreviation and the sentence:

• Canada has enjoyed a long, friendly relationship with the U.S.

How to use a period

Compared to other punctuation marks, the period is relatively easy to use. However, there are some things to be aware of.

Capitalize the first word after a period

Typically, the first word of a new sentence following a period begins with a capital letter regardless of what the word is. For example,

• My dog is a German Shepherd. She is friendly.
• The sun is really hot. Everyone knows that.
• The song was written by Leopold von Strauss. Von Strauss wrote many sonatas.

One rare exception to this rule is if a sentence begins with a company or brand name that uses a lowercase letter. For example,

• Apple makes many different products. iPhones make them a lot of money.
• People like shopping online. eBay is still a very popular website.

A sentence with an indirect question ends in a period

Sentences that are direct questions typically end with a question mark and not a period:

• Direct question: What is your name?

If a sentence states an indirect question, it is typically advised that it instead use a period:

• Indirect question: She asked me what my name was.

You need to be careful because sometimes it is difficult to tell if a sentence is asking a direct or indirect question, especially if the wording of a question has been rearranged. For example,

• Direct question: Where is the bathroom?
• Also a direct question: The bathroom is where?
• Indirect question: I wonder where the bathroom is.

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