Independent Clauses: A Complete Guide

An independent clause, also called a main clause, is a grammatical construction with a subject and a predicate. 

It expresses a complete thought and can stand independently as a complete sentence if it has end punctuation. Independent clauses are foundational in clear and engaging writing. 

The most common errors with independent clauses involve joining them, but these mistakes can be avoided by remembering a few key rules. Let’s take a closer look at best practices for writing independent clauses.

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What Makes a Clause Independent?

A clause is a grammatical construction with a subject and a predicate; some types of clauses are complete and can make a sentence. These are independent clauses. 

Other clauses have an element that makes them unable to stand on their own as a complete thought — a subordinating word — which makes them dependent clauses. Subordinating words are introductory words, such as because, when, if, and although.

Independent clause examples: 

• Mary uses an umbrella. (subject: Mary, predicate: uses an umbrella)
• Mary uses an umbrella when it rains. (subject: Mary, predicate: uses an umbrella when it rains)
• Mary uses an umbrella because it’s raining. (subject: Mary, predicate: uses an umbrella because it’s raining)

Dependent clause examples: 

• When it rains (subject: it, predicate: rains — but not a complete thought)
• Because it’s raining (subject: it, predicate: it’s raining — but not a complete thought)

Dependent clauses must be attached to an independent clause to be part of a complete sentence. They are not sentence fragments, which lack a subordinating word. 

Example of a Sentence Fragment: Mary uses an umbrella when

Why Are Independent Clauses Important?

Independent clauses are a basic and foundational part of English grammar. While they are straightforward in their construction, their significance in forming a complete thought goes a long way in writing. Knowing how to recognize independent from dependent clauses is a key skill for writers. 

Independent clauses are the foundation of clear communication

Without them, a writer cannot express a complete thought. A string of dependent clauses would have low readability and fail to engage a reader. 

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Independent clauses create sentence variety

Independent clauses are also important because they are essential in building more complex sentences. They can connect with dependent clauses to form compound and complex sentences, which provides the variation in sentence length and structure that makes language interesting. 

Knowing how to identify independent clauses helps with punctuation

By knowing what makes a clause dependent or independent, a writer learns where to place end punctuation and what type to use. 

Comma splices and run-on sentences are easily corrected when a writer understands what is needed to combine complete and incomplete thoughts. 

How to Form Compound and Complex Sentences

Without an independent clause, a writer cannot form a compound or complex sentence. The independent clause is the anchor for all sentence types.

Example using the independent clause: the coffee was hot:

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Compound sentences, coordinating conjunctions, and comma splices

When connecting two independent clauses, a coordinating conjunction is needed. A comma must be placed before the coordinating conjunction (for, and, nor, but, or, yet, so) to join the two independent clauses properly. 

When a comma is missing between two independent clauses, it’s called a comma splice:

• Incorrect: The coffee is hot it spilled on my shirt.

This can be corrected by using a semicolon, a coordinating conjunction, or a period.

• The coffee was hot; it spilled on my shirt.
• The coffee was hot, and it spilled on my shirt.
• The coffee was hot. It spilled on my shirt.

Complex sentences and subordinating conjunctions

A subordinating conjunction (because, although, when, if, etc.) is needed to join the independent and dependent clauses in complex sentences. 

As well as a subordinating conjunction you will also usually need a comma for proper grammar. However, you can skip the comma if the independent clause is first.

Examples of complex sentences and subordinating conjunctions:

• When it pours, the coffee is hot. 
  
  • The subordinating conjunction comes before the independent clause so a comma is required.
• The coffee is hot when it pours.
  
  • The subordinating conjunction comes after the independent clause so a comma isn’t required.

Compound-complex sentence formation

When two or more independent clauses are connected to at least one dependent clause, the rules above for conjunctions and punctuation apply. 

For clarity, it is essential to keep track of which clauses are linked and add punctuation accordingly:

• When it poured, the coffee was hot, and it spilled on my shirt! (Dep + Ind + Ind)
• The coffee was hot, and it spilled on my shirt when it poured. (Ind + Ind + Dep)

Final Thoughts

While at first, the concept of an independent clause may seem like elementary grammar, it’s easy to see just how critical they are in writing. From expressing complete thoughts and forming more complex sentences to avoiding comma splices and run-on sentences, independent clauses are the backbone of strong, engaging writing. 

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Then, discover more grammar best practices in our top resources:

• Declarative Sentences: A Complete Guide
• What Are Verb Tenses? 12 Types of Verb Tenses
• Common vs. Proper Nouns: A Comparative Guide
• 8 Best Practices for Web Content Editing