Expand on vs. Expand upon – Which is Correct?
Both “expand on” and “expand upon” are correct English phrases, and they usually mean to add detail or explain something more fully. “Expand on” is more common and natural in everyday writing, while “expand upon” sounds slightly more formal or emphatic. Choose either based on tone, context, and your emphasis.
Because expand describes making something broader, it is useful to distinguish it from Extend vs. Expand when choosing the precise verb.
Expand on or Expand upon – Which is Correct?
Both “expand on” and “expand upon” are correct. They are phrasal verbs that mean to provide more information, explanation, or detail about a subject. In most sentences, they can be substituted for each other without changing the basic meaning.
“Expand on” is the more common choice in everyday American English. It sounds direct, natural, and conversational. “Expand upon” has the same meaning but often creates a slightly more formal, deliberate, or emphatic tone. It is especially common in academic writing, business communication, presentations, and formal discussions.
The Best Trick to Remember the Difference
Use the shorter-for-everyday-writing rule: choose “expand on” when you simply want someone to add information. Choose “expand upon” when you want the sentence to sound more formal or carefully developed.
A useful swap test is to replace the phrase with explain in more detail. If the sentence still makes sense, either phrase will usually work. For example, “Could you expand on your proposal?” and “Could you expand upon your proposal?” are both grammatical. The first sounds more natural in conversation; the second sounds more formal.
| Word | Part of Speech | Meaning | Example |
|---|---|---|---|
| expand on | Phrasal verb | To add information or explain something in greater detail | The speaker expanded on the main benefits of the plan. |
| expand upon | Phrasal verb | To develop or explain an idea more fully | The report expands upon the findings of the earlier study. |
How to Use Expand on
Use “expand on” when asking someone to provide additional information or when describing the development of an idea. The phrase is common in speech, email, journalism, education, and general business writing. It is neither incorrect nor overly casual, although it tends to sound less formal than “expand upon.”
“Expand on” is usually followed by a noun, noun phrase, or pronoun identifying the subject being explained. Common patterns include expand on an idea, expand on a point, expand on a statement, and expand on the details.
Example 1: Could you expand on the reasons for the proposed schedule change?
Example 2: The teacher expanded on the historical background of the novel.
Example 3: In the interview, the scientist expanded on how the technology works.
Etymology of the Phrase Expand on
The verb expand comes from the Latin expandere, meaning “to spread out” or “to stretch out.” English later developed the figurative sense of making an idea broader or more detailed. The preposition on helps identify the subject receiving additional explanation, creating the modern phrasal verb “expand on.”
How to Use Expand upon
Use “expand upon” in the same grammatical situations as “expand on.” The meaning is essentially identical, but “upon” can give the phrase a more formal, polished, or emphatic quality. This makes it suitable for academic essays, formal reports, professional presentations, policy documents, and carefully edited prose.
Although “expand upon” is grammatically correct, it can sound slightly more elevated than necessary in casual conversation. In an informal email, “Can you expand on that?” will usually sound more natural than “Can you expand upon that?”
Example 1: The author expands upon the central argument in the second chapter.
Example 2: The director expanded upon the company’s long-term sustainability goals.
Example 3: The professor asked students to expand upon their initial conclusions.
Etymology of the Phrase Expand upon
“Expand upon” combines the Latin-derived verb expand with upon, a form historically related to the idea of position or contact. English has long used upon in formal and literary expressions. In this phrase, it indicates the idea or subject on which additional explanation is built.
Related Concepts
Understanding phrasal verbs, prepositions, and register helps explain why “expand on” and “expand upon” can both be correct while creating slightly different impressions.
- Phrasal verbs: A phrasal verb combines a verb with a short word such as a preposition or adverb. In “expand on” and “expand upon,” the complete phrase means to develop or explain an idea more fully.
- Register: Register refers to the level of formality used in language. “Expand on” generally has a neutral register, while “expand upon” often has a more formal or deliberate register.
- Prepositions: “On” and “upon” can sometimes perform similar grammatical functions. In this expression, both introduce the topic receiving further explanation.
- Synonyms: Words such as “elaborate,” “develop,” “clarify,” and “explain” can replace either phrase in suitable contexts.
Examples from Media and Literature
Both phrases appear across journalism, fiction, academic writing, and professional communication. The following examples show how each form works in realistic contexts:
- News reporting: A journalist may write that an official “expanded on the government’s response” during a press conference.
- Academic writing: A researcher may state that a later section “expands upon the framework introduced in the previous chapter.”
- Literary criticism: A critic might explain that a novel expands on themes introduced in an earlier work by the same author.
- Film interviews: An interviewer may ask a director to expand on the meaning behind a particular character or scene.
- Business presentations: A presenter may expand upon a proposed strategy by discussing its costs, risks, and expected results.
Practice Exercises
Choose the phrase that best completes each sentence. In most cases, both options are grammatically possible, but consider the tone of the sentence.
- Could you ______ your comments about the new marketing plan? (expand on / expand upon)
- The formal report ______ the principles established in the original policy. (expands on / expands upon)
- During the casual conversation, Maya asked her colleague to ______ his unusual proposal. (expand on / expand upon)
- The author ______ the consequences of the decision in the final chapter. (expands on / expands upon)
- The professor invited the student to ______ the evidence supporting her conclusion. (expand on / expand upon)
Answer Key
- expand on — This is the more natural choice for a casual request, although “expand upon” is also correct.
- expands upon — The formal tone of the report makes “expands upon” a suitable stylistic choice.
- expand on — “Expand on” sounds more conversational.
- expands upon — The formal, analytical context suits “expands upon.”
- expand on — This neutral academic request works naturally with “expand on,” though “expand upon” is also grammatical.
Expand on Synonyms
| Synonym | Definition |
|---|---|
| elaborate on | To provide additional information or explanation |
| explain | To make an idea or subject easier to understand |
| develop | To build an idea or argument in greater detail |
| clarify | To make a statement or concept more precise or understandable |
Expand upon Synonyms
| Synonym | Definition |
|---|---|
| elaborate upon | To explain or develop a subject with additional detail |
| further discuss | To continue examining or explaining a topic |
| expound on | To explain an idea in a detailed and often formal way |
| amplify | To add information that strengthens or clarifies an explanation |
Frequently Asked Questions
Question 1: Is “expand on” grammatically correct?
Yes. “Expand on” is grammatically correct and is the more common version in everyday American English. It means to add detail or explain a subject more fully.
Question 2: Is “expand upon” more correct than “expand on”?
No. Neither phrase is more grammatically correct. “Expand upon” is simply a somewhat more formal or emphatic alternative to “expand on.”
Question 3: Should I use “expand on” or “expand upon” in formal writing?
Both are acceptable in formal writing. “Expand upon” may better suit a highly formal tone, but “expand on” is clear, concise, and widely accepted in academic and professional contexts.
Question 4: Can “expand on” and “expand upon” be used interchangeably?
Usually, yes. They have the same basic meaning and can generally replace one another. The main difference is stylistic: “expand on” is more neutral, while “expand upon” often sounds more formal.
Conclusion
“Expand on” and “expand upon” are both correct phrases meaning to add detail or explain an idea more fully. Use “expand on” for the most natural everyday wording, and choose “expand upon” when a more formal or emphatic tone is appropriate. Pro Tip: In professional writing, prioritize clarity and consistency rather than using “upon” simply to sound more sophisticated.
