How They Differ? Subordinating vs. Coordinating Conjunctions

Contents

In this article, we’ll look at following points:

The key difference between subordinating and coordinating conjunctions
How they are used differently in sentences
Common examples of subordinating and coordinating conjunctions

Conjunctions

Conjunctions are one of the parts of speech (word category) that serve two main functions in a sentence:

Connect two clauses
List two or more items (e.g., I like cats and dogs.)

Using the first type of conjunction correctly is especially important in English grammar. Without it, you may create a grammatical mistake called a run-on sentence.

I was tired, so I went to bed early.

This sentence is correct because the two independent clauses, “I was tired” and “I went to bed early,” are properly connected with the conjunction “so.”

In contrast, the two sentences below are ungrammatical because they lack a conjunction to connect the two independent clauses.

* I was tired, I went to bed early.

* I was tired I went to bed early.

As you can see, both sentences lack the conjunction or proper punctuation needed to join two independent clauses.

The first sentence connects two complete thoughts with only a comma. This error is called a comma-splice, which happens when two independent clauses are joined with just a comma.

The second sentence simply places two independent clauses side by side without any connector. This creates a run-on sentence, another common grammatical mistake in English.

To avoid comma splices and run-on sentences, you need to use conjunctions correctly and carefully. In this article, we’ll focus on the first type of conjunction: the ones that connect two clauses.

Two Types of Conjunctions that Connect Clauses

Text showing the title 'Conjunctions' followed by two bullet points: 'Coordinating Conjunctions' and 'Subordinating Conjunctions' written on a lined white background.

When it comes to conjunctions that link clauses, there are two main types: coordinating and subordinating conjunctions.

A coordinating conjunction connects two independent clauses, while a subordinating conjunction links a dependent clause to an independent clause.

In this section, we’ll look more closely at how these two types differ in structure and meaning.

Coordinating Conjunctions

This type of conjunction is used to link two independent clauses.

Be careful! You normally need to place a comma before a coordinating conjunction. This is the key structural difference between coordinating and subordinating conjunctions.

Comma + Coordinating Conjunction

When connecting two independent clauses, the structure should follow this pattern:

Independent clause + comma + conjunction + independent clause

So, which words count as coordinating conjunctions? They can be easily remembered with the famous acronym FANBOYS.

Acronym of Six Coordinating Conjunctions: FANBOYS

FANBOYS is an acronym formed from the initial letter of each of the seven coordinating conjunctions:

For
And
But
Or
Yet
So

These conjunctions are called coordinating because they link two independent clauses of equal importance. When you use one of these conjunctions, place a comma before it, unless another grammatical rule takes priority.

I wanted to go for a walk, but it started raining.

The two independent clauses, “I wanted to go for a walk” and “it started raining,” are joined by the coordinating conjunction “but.”

The experiment was successful, and we submitted the report.

Here, “the experiment was successful” and “we submitted the report” are connected by “and.”

Coordinating Conjunction without a Comma

However, coordinating conjunctions such as “and” and “but” don’t always need a comma before them. There’s one specific condition where the comma should be omitted.

Condition

If two independent clauses connected by “and” or “but” share the same subject, and the second subject is omitted, do not use a comma.

This rule can feel a bit abstract at first, so let’s look at some examples to see how it works in real sentences.

She smiled and waved.

As we’ve learned, “and” is a coordinating conjunction and normally takes a comma before it when joining two independent clauses. In this case, however, both parts share the same subject.

She smiled.
(She) waved.

Since the subject “she” appears twice, it can be omitted from the second clause. When we do that, the comma is also removed. That’s why there’s no comma before “and” in the sentence “She smiled and waved.”

We can apply the same rule for the coordinating conjunction “but” as well.

He came here but soon left the room.

Here, two independent clauses are connected by the coordinating conjunction “but.” You may notice that both clauses share the same subject “he,” but it is omitted in the second clause.

Because the subject is omitted, the comma before “but” is also removed.

Subordinating Conjunctions

Simply put, subordinating conjunctions are conjunctions other than FANBOYS.
Grammatically, they are the words that introduce dependent clauses and connect them to independent clauses. One key difference between subordinating and coordinating conjunctions lies in where they can appear within a sentence.

Key Property of Subordinating Conjunctions

Subordinating conjunctions can appear in two possible positions within a sentence:

At the beginning of a sentence — comma required
In the middle of a sentence — no comma required

For example, the following two sentences using the subordinating conjunction “though” have exactly the same meaning, but the position of the conjunction differs.

I like school though I don’t feel like going this morning.

Though I like school, I don’t feel like going this morning.

When a subordinating conjunction appears at the beginning of a sentence, the dependent clause that it introduces must be followed by a comma before the independent clause. In the example above,

Dependent clause: Though I like school
Independent clause: I don’t feel like going this morning

These two clauses are separated by a comma.

In contrast, when the dependent clause comes after the independent clause, no comma should be used before the conjunction.

This rule also applies to other subordinating conjunctions such as because, although, when, while, since, and if.

About the Author: joe

Hi, I’m Joe. I completed my BA and MA at Purdue University. My research topic was effectiveness and reliability of standardized tests like the SAT and TOEFL. After that, I worked in the test development industry and designed questions to make sure they reflected the skills of interest. I’ve spent time on both the research side and the practical side of test design, and I want to support SAT learners here. Having seen how test questions are actually made, I can give students effective strategies for SAT test takers.