Commas with Independent Clauses
The Blue Book of Grammar and Punctuation
Commas with Independent Clauses
NOTE: An independent (or strong) clause is a simple sentence with a subject, verb, and a complete thought. A dependent (or weak) clause has a subject and verb but does not express a complete thought.
Rule – Use a comma to separate two independent clauses joined by a coordinating conjunction—and, or, but, for, nor. You may omit the comma if the clauses are both short.
Examples:
I have painted the entire house, but he is still working on sanding the doors.
I paint and he writes.
Rule – A comma splice is an error caused by joining two independent clauses with only a comma instead of separating the clauses with a conjunction, a semicolon, or a period. A run-on sentence, which is incorrect, is created by joining two strong clauses without any punctuation.
Examples:
Incorrect:
Time flies when we are having fun, we are always having fun. (Comma splice)
Time flies when we are having fun we are always having fun. (Run-on sentence)
Correct:
Time flies when we are having fun; we are always having fun.
OR
Time flies when we are having fun, and we are always having fun.
OR
Time flies when we are having fun. We are always having fun.
Pop Quiz
Choose the correct sentence.
1A. Morgan did all of the grocery shopping but all Ralph did was watch the game.
1B. Morgan did all of the grocery shopping, but all Ralph did was watch the game.
2A. Morgan shopped but Ralph watched the game.
2B. Morgan shopped, but Ralph watched the game.
3A. Alphonso’s home sits high on the hill, you can see Mt. Diablo from there.
3B. Alphonso’s home sits high on the hill you can see Mt. Diablo from there.
3C. Alphonso’s home sits high on the hill, and you can see Mt. Diablo from there.
3D. Alphonso’s home sits high on the hill; you can see Mt. Diablo from there.
4A. I don’t know whether we’ll get home tonight. We still have a long way to go.
4B. I don’t know whether we’ll get home tonight, for we still have a long way to go.
4C. I don’t know whether we’ll get home tonight we still have a long way to go.
Pop Quiz Answers
1B. Morgan did all of the grocery shopping, but all Ralph did was watch the game.
2A. Morgan shopped but Ralph watched the game. OR
2B. Morgan shopped, but Ralph watched the game.
(You may omit the comma if the clauses are both short.)
3C. Alphonso’s home sits high on the hill, and you can see Mt. Diablo from there. OR
3D. Alphonso’s home sits high on the hill; you can see Mt. Diablo from there.
(3A. is a comma splice. 3B. is a run-on sentence.)
4A. I don’t know whether we’ll get home tonight. We still have a long way to go. OR
4B. I don’t know whether we’ll get home tonight, for we still have a long way to go.
(4C. is a run-on sentence.)
If the article or the existing discussions do not address a thought or question you have on the subject, please use the "Comment" box at the bottom of this page.
On your website, you recommend using a semicolon instead of a comma before a coordinating conjunction to join two strong clauses together when the first sentence already has a comma or commas; however, I’ve seen many publications use a comma or even a period. Are these unrecommended alternatives or are these simply incorrect?
In the latest editions of two leading grammar reference books, I can only find the following two rules:
AP Stylebook’s rule states, “If a coordinating conjunction is present, use a semicolon before it only if extensive punctuation also is required in one or more of the individual clauses: They pulled their boats from the water, sandbagged the retaining walls, and boarded up the windows; but even with these precautions, the island was hard-hit by the hurricane.”
The Chicago Manual of Style’s rule 6.58 says, “When items in a series themselves contain internal punctuation, separating the items with semicolons can aid clarity. If ambiguity seems unlikely, commas may be used instead.”
Therefore, I will likely revise Semicolons Rule 5 in the future to the effect that, “A semicolon may be used . . .” rather than “Use the semicolon . . .”
I was looking up comma rules as I was writing a paper and saw your website. I found it helpful, but I found different explanations on other websites. I
found the following example unclear:
Rule 12
Use a comma to separate two strong clauses joined by a coordinating conjunction–and, or, but, for, nor. You can omit the comma if the clauses are both short.
Examples:
I have painted the entire house, but he is still working on sanding the doors.
I paint and he writes.
When referring to strong clauses, do you mean independent clauses? “He writes,” seems to be a complete sentence. “He” is the subject and “writes” is the verb, right? The coordinating conjunction is “and,” so I am a little
confused. Is it because “he” is a pronoun? If you could clarify this for me, I would appreciate it.
We are not clear on why you’re confused. Yes, by strong clauses we mean independent clauses. Yes, both I write and he paints are independent clauses. Note that they are both short (can’t get much shorter). Therefore, we have chosen to omit the comma in that example as per the second sentence of Rule 12.
Is a comma necessary in the following sentence:
Gentle words lift up and grow like a tree, spreading from person to person and making life more enjoyable and fruitful.
I don’t know if the last part of the sentence is a nonessential phrase – no comma or if it is just an extra explanation of the first part of the sentence.
Another example:
The doctor, following a lengthy vacation, was ready to get back to work.
or
The doctor was ready to get back to work, following a lengthy vacation.
A comma is needed in the last part of your first sentence because otherwise, readers would think “spreading” applies to “tree,” when in fact it describes “gentle words.” Only a comma could steer the reader back to “words,” as the writer intended.
Commas are needed in the second example to set off an expression that interrupts sentence flow. We would not advise the final sentence as it sounds as if work was on a lengthy vacation.
The sentence is: The President, or in his/her absence, the Vice President, shall preside at all meetings.
I’m thinking the phrase “in his/her absence” should be set off by commas and the one after “President” isn’t necessary. Thus, “The President or, in his/her absence, the Vice President, shall preside at all meetings.”
Which is correct?
You are correct regarding commas; the sentence should be The president or, in his or her absence, the vice president shall preside at all meetings. Note that we recommend against use of the slash in formal writing. We also side with the Chicago Manual of Style in spare use of capitals—sometimes referred to as a “down” style (see our Rule 4 of Capitalization).
There is a small grammatical error of comma usage on your fantastic website at https://www.grammarbook.com/grammar/pronoun.asp:
“Someone has to do it, and has to do it well.”
The comma splits a compound predicate, a non-standard construction.
As we mention in Rules for Commas, commas customarily indicate a brief pause. Although the comma is not required in the sentence, the comma underscores an intended stylistic effect. This is an instance of bending the rules being acceptable as long as the writer understands what the rules are.
Is the following punctuation correct or should the comma be deleted? The sentence is short but not quite as short as the five word sentence (“I paint and he writes.”) you use as an example. I prefer the comma.
“Love yourself, and be proud of yourself.”
The comma is correct; however, it can be omitted as a stylistic choice for what is still a short pair of sentences.
Would the following sentence be “short” or “weak” enough to omit a comma?
The bar wasn’t packed but it wasn’t empty.
Yes, depending on your style and preference, you could write the sentence with or without a comma separating the short independent clauses.