Punctuation
Using Periods and Commas Correctly
There are many rules for using commas and periods in English.
Here is what you need to know:
Spacing
Use one space after a comma.
Use two spaces after a period.
Do NOT use spaces before commas and periods.
Complete and Incomplete Sentences
Periods are used to separate complete sentences.
Commas are used to separate ideas within sentences.
Commas are often used after certain words and groups of words (phrases and clauses).
Groups of words followed by commas are not sentences by themselves.
They need to be combined with other sentences to be complete.
Positions of Phrases within Sentences
Phrases and clauses can be used in three sentence positions:
Introductory: before the main subject (A comma is needed to separate the phrase from the subject.)
Intermediary: between the subject and main verb (Commas are needed before and after the phrase.)
Final: At the end of the sentence. (No commas are required here.)
See also: