The short answer
Paraphrasing is not plagiarism when you cite the source and write the idea in your own words and sentence structure. It is plagiarism in two cases:
- You do not cite the source. The words are yours, but the idea is not.
- You stay too close to the original. You keep the author’s sentence and only change a few words. This counts even with a citation.
So a good paraphrase needs two things: your own wording and a citation. If one is missing, it is plagiarism.
| What you did | Is it plagiarism? |
|---|---|
| Own words and structure, with a citation | No. This is a correct paraphrase. |
| Own words and structure, no citation | Yes. The idea is presented as yours. |
| A few words swapped, with a citation | Yes. The wording is still the author’s. |
| A few words swapped, no citation | Yes. Both the idea and the wording are taken. |
When paraphrasing is not plagiarism
Paraphrasing is a normal part of academic writing. Most of the sources in a good essay are paraphrased, not quoted. The Purdue OWL page on paraphrasing describes a paraphrase as a legitimate way to borrow from a source “when accompanied by accurate documentation”.
A paraphrase is fine when all of these are true:
- The source is cited. There is an in-text citation next to the paraphrase and a full entry in your reference list.
- The wording is yours. You chose the words. You did not edit the author’s sentence.
- The structure is yours. The sentence starts in a different place and is built in a different way.
- The meaning is accurate. You report what the source says and nothing more.
Technical terms, names and numbers can stay the same. “Photosynthesis” has no other word. Keeping it is not plagiarism.
When paraphrasing is plagiarism
The MLA Style Center puts it plainly: “Paraphrasing someone’s ideas or arguments or copying someone’s unique wording without giving proper credit is plagiarism.” These are the usual ways it happens.
- No citation. You restate the idea well but do not say where it came from.
- Synonym swapping. You keep the author’s sentence and replace some words. The UNC Writing Center notes that paraphrasing does not mean “changing a word or two in someone else’s sentence” or “changing a few words to synonyms”. This is often called patchwriting.
- Borrowed phrases without quotation marks. Your sentence is mostly your own, but it carries the author’s distinctive phrases. See mosaic plagiarism.
- A citation in the wrong place. The source is in your reference list but not next to the paraphrase. The reader cannot tell which ideas came from it.
- Your own old work, reworded. Paraphrasing a paper you already submitted, without permission, can be self-plagiarism.
Many of these happen by mistake, for example when notes mix copied text with your own words. Most policies still treat the result as plagiarism. See our guide to accidental plagiarism.
Side by side: acceptable vs plagiarized paraphrase
The source passage below was written for this guide. The author and the book are invented, so nothing is taken from a real publication.
Original source
“Street trees cool a city in two ways. Their leaves shade the pavement, so it absorbs less heat during the day, and they release water vapor, which lowers the temperature of the air around them.” (Lindqvist, 2023, p. 88)
| Acceptable paraphrase | Plagiarized paraphrase | |
|---|---|---|
| Text | Planting trees along roads is a practical way to bring down urban temperatures. Lindqvist (2023) explains that the canopy keeps sunlight off hard surfaces, and that moisture given off by the leaves cools the nearby air (p. 88). | Street trees cool a town in two ways. Their foliage shades the pavement, so it absorbs less heat in the daytime, and they release water vapor, which reduces the temperature of the air around them. |
| Wording | New. Only plain words such as “trees”, “leaves” and “air” are shared. | Mostly the author’s. The highlighted words are copied. A few synonyms were swapped in. |
| Structure | New. It opens with the writer’s own point and joins the two effects in one sentence. | The same two sentences, in the same order, with the same clauses. |
| Citation | Yes. The author is named, with year and page. | None. |
| Verdict | Not plagiarism. | Plagiarism. |
Adding “(Lindqvist, 2023)” to the right-hand version would not fix it. The citation would credit the idea, but the sentences would still be the author’s, presented as the writer’s own. To fix it, either put the copied words in quotation marks or write the point again from what you understood.
For the method, see our step-by-step guide on how to paraphrase without plagiarizing.
Plagiarism vs paraphrasing: the difference
Paraphrasing is a writing skill. Plagiarism is a breach of academic honesty. They are not opposites: a paraphrase can be honest or plagiarized, depending on how it is done.
| Paraphrasing | Plagiarism | |
|---|---|---|
| What it is | Restating a source’s idea in your own words and structure. | Presenting someone else’s words or ideas as your own. |
| Credit | The source is cited. | The source is missing, or the copied wording is not marked. |
| Whose words | Yours. | The author’s, or the author’s with small edits. |
| What the reader learns | Where the idea came from, and that you understood it. | A false picture of where the idea or the wording came from. |
| Allowed? | Yes. It is expected in academic writing. | No. |
Plagiarized paraphrasing is one of several kinds of plagiarism. Our guide to the types of plagiarism lists the others.
A quick checklist
Run through this for each paraphrase before you submit.
- Is the source cited next to it? An entry in the reference list alone is not enough.
- Could I have written this with the source closed? If you needed the original open to build the sentence, it is probably too close.
- Is the sentence built differently? Compare the order of ideas with the original.
- Are any distinctive phrases the author’s? Put them in quotation marks or replace them.
- Is the meaning still accurate? A paraphrase must not add to or change what the source says.
- Is the source in my reference list? The citation generator formats the in-text citation and the reference entry.
What a similarity report shows
A plagiarism checker compares your wording with other texts. That tells you some things about a paraphrase and not others.
- It shows wording you kept. A paraphrase that stayed close to the source usually appears as short highlighted matches that all point to one source.
- It does not show missing citations. A paraphrase in your own words will usually not match anything. If it has no citation, it is still plagiarism. The report cannot see that.
- Not every match is a problem. Quoted and cited text, titles and technical terms can match too.
So use the report to find passages to review, not as a verdict. When a paraphrase is highlighted, open the source and compare. Then choose: quote the words and cite them, or write the idea again from what you understood and cite it. The goal is honest credit, not a lower number.
In the Plagiarism Checker Plus plagiarism checker, each matching passage is highlighted and linked to its source, so you can make that comparison quickly. Our guide on how to interpret a plagiarism report explains what the percentage does and does not mean.