Due To vs Because Of: Grammar Guide for ESL Learners

Introduction

Do you ever pause mid-sentence, wondering whether to write “due to” or “because of”? You are not alone. Even advanced English learners often mix these two phrases up, and the difference is more than just formality—it is about grammar. Understanding the correct usage will instantly make your writing sound more polished, whether you are sending a work email, writing an academic essay, or chatting casually with friends.

What Is “Due To” vs “Because Of”?

Both “due to” and “because of” explain reasons or causes. They answer the question “Why?” However, they belong to different grammatical categories, which changes how you use them in a sentence.

“Because of” is a preposition. It is always followed by a noun phrase. It modifies the entire clause, telling us why something happened.

“Due to” is technically an adjective phrase. It modifies a noun, not a verb. In strict formal grammar, “due to” should follow a form of the verb “to be” (is, was, were, etc.).

Think of it this way: if you can replace “due to” with “caused by,” you are using it correctly. If you can replace “because of” with “as a result of,” you are on the right track.

Rules

1. “Because of” always follows a verb or a clause. It explains why the action in the main verb happened. Example: The game was cancelled because of rain.
2. “Due to” must follow a noun and a form of “to be.” It modifies the noun right before it. Example: The cancellation was due to rain.
3. “Due to” can be replaced with “caused by.” If the sentence still makes sense, you have used it correctly. Example: The delay was caused by traffic.
4. “Because of” can be replaced with “owing to.” This is a good test for prepositions. Example: We stayed home owing to the storm.
5. Never start a sentence with “due to” in formal writing. If you must start a sentence, use “because of” or rephrase. Example: Because of the weather, we stayed inside.
6. In casual speech, “due to” is often used like “because of.” Many native speakers do this, but for exams and formal writing, you should follow the strict rule.
7. “Due to” is an adjective phrase, so it needs a noun to modify. It cannot stand alone at the beginning of a sentence in formal grammar.

How to Use It

Follow these simple steps to choose the correct phrase every time.

1. Identify what you are explaining. Ask yourself: Am I explaining why a verb happened, or am I describing a noun?
2. Check the sentence structure. Look for the main verb. If the reason follows the main verb and modifies the action, use “because of.”
3. Look for a form of “to be.” If your sentence has “is,” “was,” “were,” or “has been,” and the reason follows it, you can use “due to.”
4. Try the replacement test. Substitute “caused by” for “due to.” If it sounds natural, keep it. Substitute “as a result of” for “because of.” If it works, you are correct.
5. Consider your audience. For academic essays, business reports, or IELTS writing, use the strict rules. For casual emails or text messages, either is acceptable, but “because of” is safer.

Examples in Sentences

Here are ten sentences showing the correct usage. Notice the bolded phrases.

• The outdoor concert was postponed because of the thunderstorm.
• His success in the exam was due to months of dedicated study.
• She missed the meeting because of a family emergency.
• The flight delay was due to mechanical issues with the aircraft.
• We arrived late because of heavy traffic on the highway.
• The increase in sales was due to the new marketing campaign.
• Many students struggle with grammar because of inconsistent teaching methods.
• The cancellation of the event was due to low ticket sales.
• He couldn’t sleep because of the loud noise from the construction site.
• The company’s financial losses were due to poor investment decisions.

Common Mistakes

Here are the most frequent errors ESL learners make, with corrections.

• Mistake 1: Starting a sentence with “due to.”
  ❌ Due to the rain, the match was cancelled.
  ✅ The match was cancelled due to the rain.
  ✅ Because of the rain, the match was cancelled.
• Mistake 2: Using “due to” after a normal verb.
  ❌ He failed the test due to he didn’t study.
  ✅ He failed the test because of his lack of study.
  ✅ He failed the test because he didn’t study. (Note: “because” + subject + verb)
• Mistake 3: Adding a full clause after “because of.”
  ❌ She was happy because of she got a promotion.
  ✅ She was happy because of her promotion.
  ✅ She was happy because she got a promotion.
• Mistake 4: Using “due to” without a form of “to be.”
  ❌ The event was cancelled due to the organizers wanted more time.
  ✅ The event was cancelled due to the organizers’ request for more time.
  ✅ The event was cancelled because of the organizers’ request.
• Mistake 5: Confusing “due to” with “due.”
  ❌ The payment is due to tomorrow.
  ✅ The payment is due tomorrow. (Here, “due” means expected or required.)

Quick Summary

• “Because of” is a preposition followed by a noun phrase. It modifies a verb or a clause.
• “Due to” is an adjective phrase that follows a form of “to be.” It modifies a noun.
• Use the “caused by” test for “due to.”
• Use the “as a result of” test for “because of.”
• In formal writing, avoid starting a sentence with “due to.”
• In casual conversation, native speakers often use them interchangeably, but exams and business writing require precision.

Practice Exercises

Fill in the blanks with either “due to” or “because of.” Answers are below.

1. The picnic was cancelled __________ the unexpected snowstorm.
2. Her excellent performance in the interview was __________ her thorough preparation.
3. We couldn’t see the stage clearly __________ the poor lighting.
4. The project’s failure was __________ a lack of communication among team members.
5. He moved to a new city __________ a better job opportunity.

Answers:

1. because of (modifies the verb “was cancelled”)
2. due to (follows “was” and modifies “performance”)
3. because of (modifies the verb “couldn’t see”)
4. due to (follows “was” and modifies “failure”)
5. because of (modifies the verb “moved”)

Conclusion

Mastering the difference between “due to” and “because of” is a small change that makes a big impact on your English accuracy. Remember the golden rule: “because of” explains actions, while “due to” describes nouns. With regular practice, this will become second nature. Keep writing, keep testing yourself, and soon you will choose the correct phrase without even thinking.

FAQ

1. Can I use “due to” at the beginning of a sentence?

In strict formal grammar, no. “Due to” is an adjective phrase, so it needs to follow a noun and a form of “to be.” However, in modern casual English, many native speakers do start sentences with “due to.” For IELTS, TOEFL, or business writing, it is safer to use “because of” at the start of a sentence.

2. What is the difference between “due to” and “owing to”?

“Owing to” is a preposition like “because of” and is considered more formal. You can often swap “owing to” and “because of” without changing the meaning. “Due to” is different because it is an adjective phrase. Example: The delay was owing to bad weather. (Here, “owing to” works, but “due to” is also acceptable in modern usage.)

3. Is it ever acceptable to use “due to” like “because of”?

Yes, in everyday spoken English and informal writing, this is very common. You will hear sentences like “Due to the traffic, I was late.” Many respected publications now accept this. However, for grammar exams or formal academic writing, you should follow the traditional rule: “due to” must follow a form of “to be.”

4. What is the easiest trick to remember the difference?

Think about the word “due.” It means “owed” or “attributable.” So “due to” means “attributable to.” If you can say “attributable to” in the sentence, use “due to.” For “because of,” think of it as “for the reason of.” If you can say “for the reason of,” use “because of.” This mental shortcut will help you choose correctly every time.