The Best Comma Rule Ever

When an editor explained this rule, something that had always baffled me finally made sense. Look at this sentence:

Michael sat at his desk and dreamed about the girl he had met just that morning.

Many of my CWG Apprentice students would use a comma after desk. After all, we pause there when we read it out loud. But is the comma correct? What about this sentence?

Michael sat at his desk and he dreamed about the girl he had met just that morning.

Here’s how to tell whether to use a comma: Is it a compound sentence—two complete sentences joined by a conjunction? You simply need to look after the conjunction and see if there’s a second subject and verb. If you find both after the conjunction, use a comma.

Consider these examples:

Sally (subject) baked (verb) the beans, and (conjunction) George (subject) stirred (verb) the stew.

There are two complete sentences, joined by and. That makes it a compound sentence. Use a comma.

Rudolph (subject) led (verb) the way, but (conjunction) Dasher (subject) followed (verb) close behind.

After the conjunction, there’s a second subject and a second verb. Use a comma.

If a sentence doesn’t have a second subject and a second verb after the conjunction, the division point doesn’t need to be marked with a comma.

Sally (subject) baked (verb) the beans and (conjunction) stirred (verb) the stew.

There’s no second subject after the conjunction. No comma.

Rudolph (subject) led (verb) the way but (conjunction) got lost (verb).

Again, there’s no second subject. No comma.

Rudolph (subject) and his buddies (subject) led (verb) the way but (conjunction) got lost (verb).

This one’s more complicated. There are two subjects and two verbs, but the second subject comes before the conjunction. After the conjunction there’s not a complete subject-and-verb sentence. No comma.

So what about those first two sentences?

Michael (subject) sat (verb) at his desk and (conjunction) dreamed (verb) about the girl he had met just that morning.

There’s no subject after the conjunction. No comma.

Michael (subject) sat (verb) at his desk and (conjunction) he (subject) dreamed (verb) about the girl he had met just that morning.

After the conjunction, there’s both a subject and a verb. Use a comma—with confidence.

To learn more about compound sentences:

● Lynn Truss, Eats, Shoots, & Leaves (New York: Gotham Books, 2003), page 87.

● Mignon Fogarty, Grammar Girl’s Quick and Dirty Tips for Better Writing (New York: Holt, 2008), pages 103–4.

Kathy Tyers is a Christian Writers Guild mentor and the author of several science fiction novels. She writes from her home in Montana.

Photo Credit: © Ivelin Radkov –


      • Andy Scheer says

        Chicago Style calls for spelling out state names, and setting them off with commas.

        AP Style calls for the non-postal system abbreviation for most states: She lived in Falmouth, Mass., and swam in the ocean.

        • Kathy Tyers says

          Andy’s correct, of course! Editing resources sometimes differ, and a particular publishing house will generally prefer Chicago Style or AP style.

          Thanks for writing, Christina.

    • Kathy Tyers says

      You are so welcome. I never would have been published if it hadn’t been for the critiquing partners in my first writing group. I try to pay them forward by helping other writers. I hope you’ll do the same.

    • Kathy Tyers says

      Me too, Peter. Also ellipses. I’m learning to trust my readers to insert those pauses. It’s hard, isn’t it? (c: Suggestion: When in doubt, take it out. If the sentence still communicates what you want the reader to know, it’s a win-win situation: happy readers and mature-looking prose.

      But if you feel that the result is honestly confusing, put it back in. Trust your EDITOR to take it out if necessary!

  1. Charlotte Wheat says

    Thank you for the simple directions that I forgot long ago.
    Also, how do we know when to use commas with word descriptions of time? In some writings I see commas setting them off and in others they are not there. Thanks for help on this.

    • Kathy Tyers says

      I’m glad you asked! Click on the text just to the right of the number “5″ (a few pararaphs above this) — where it says “News You Can Use.” That should get you there!

      If that doesn’t work, type “Steve Laube” into the Google search engine. Go to his website, then click on “blog” up at the top of the page.

  2. Barbara Pianko says

    Thank you! I think this will help me tremendously. I am in a Master’s Program and each time I submit something I have written for review prior to submission for grade I have corrections on the use of my commas!

  3. Catherine Ballay says

    In the example “Michael sat at his desk, and he dreamed about the girl. . . .” I don’t think “he” qualifies as a second subject. I would not use the comma. Or I would revise to “Michael sat at his desk, dreaming. . . .” His sitting doesn’t constitute a separate action; it just describes the setting in which he day-dreamed. No?

  4. Kathy Tyers says

    Dear Reader — if you don’t already subscribe to Steve Laube’s excellent blog, you’re missing publishing industry news, writing tips and testimonials, and “Fun Fridays” that help us keep our sense of humor. Highly recommended!


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