Best plagiarism checkers for students

The short answer

There is no single best plagiarism checker for students. The right one depends on three things:

• Does your school already give you a checker? If it does, use that one first. It is the one your work will be judged with.
• How long is your paper? Free checks have limits. A short essay may fit. A thesis usually will not.
• Do you also need an AI check? Some tools check for matching text only. Some also estimate whether text was written by AI.

Comparison table

The tools are in alphabetical order after ours. The order is not a ranking. Each cell is a fact from the maker’s own site, linked in the sources below. “Not stated” means we read the page and it did not say. Prices are the listed prices in US dollars on that date.

Prices and limits change. Before you pay for anything, read the maker’s own pricing page on the day you buy.

If your school already gives you a checker, use that first

Many schools pay for a plagiarism checker and connect it to the place where you hand in work. If yours does, that is the check that counts. Any other tool searches a different set of sources and will give a different result.

How to find out:

1. Look at the page where you submit work. It often names the tool.
2. Read the syllabus. Many courses say which checker they use.
3. Ask your teacher, the library or the IT help desk. Some schools let students check a draft before the final version.

A tool you use on your own is still useful for finding sentences that need a citation before you hand the work in. It cannot tell you what your school’s report will show.

If you want plagiarism and AI checking in one report

A plagiarism check and an AI check answer different questions. The first asks “does this text match something that already exists?” The second asks “how likely is it that an AI tool wrote this?” How AI detectors work explains the difference.

Plagiarism Checker Plus (ours)

Our plagiarism checker and AI detector run in one report. The plagiarism check links every matching source next to your text. The AI detector gives an overall score and a likelihood for each sentence. The first plagiarism check and the first AI check are free without an account, up to 1,000 words each. A free account includes 3,000 words a month. Paid plans add longer documents, folders and API access, and the prices are on our pricing page. There is a Google Docs add-on and a Chrome extension. Your text is never used to train AI.

Its limits:

• The free check stops at 1,000 words. A longer paper needs an account or a paid plan.
• The web app and the reports are in English.
• It does not connect to a school system or learning platform.
• Like any tool, it searches its own set of sources. It will not match what your school’s system shows.
• An AI score is a probability. It is not proof.

Grammarly

Grammarly’s plans page lists detecting plagiarism and AI-generated text as features of a paid plan, and does not list them in the free plan. Grammarly also has a free AI detector page. The pages we read do not say whether the plagiarism result and the AI result come in one report. The plans page showed us prices in a local currency, so check their site for current pricing where you live.

Copyleaks

Copyleaks’ pricing page says its plans scan for AI and plagiarism in a single report. The Personal plan was listed at $13.99 a month, billed yearly at $167.88. Its plagiarism checker page says you can try the checker free by registering for an account.

If you only need a quick free check

For a short text, a free check may be enough. Before you paste anything, look for three things on the tool’s page: the word limit, whether you must sign up, and whether the free result shows the sources or only a percentage.

• Plagiarism Checker Plus (ours). The first check is free without an account, up to 1,000 words, and it links the matching sources. After that you need a free account, which includes 3,000 words a month. Try it on the plagiarism checker for students page.
• Grammarly. Its plagiarism checker page lets you add text and scan it, and says you can get an originality score. It does not state a word limit, whether you must sign up to see a result, or exactly what a check without a paid plan shows.
• Duplichecker. Its home page has a free plagiarism checker. The box showed a 10,000-character counter when we opened it, and the page says it scans up to 25,000 words per search. Several settings are marked Pro, so check which limits apply to the free check.
• Copyleaks. Its plagiarism checker page says you can try it free by registering for an account. The page does not state the limit.
• QuillBot and Scribbr. Their pages list plagiarism checking as paid, so neither is a free check. See paying for one long paper.

If you also want grammar help

Some students want one tool for both checking sources and fixing sentences.

• Grammarly. Its plagiarism checker page shows results for grammar, spelling, punctuation, conciseness, readability and word choice next to the plagiarism result. Plagiarism detection itself is listed in a paid plan on its plans page.
• QuillBot. Its plagiarism checker page lists a grammar checker among its tools. The plagiarism checker itself comes with a Premium subscription.
• Plagiarism Checker Plus (ours). Our grammar checker is a separate free tool, up to 10,000 characters at a time with no sign-up. It is not part of the plagiarism report, so you run it as its own step. The essay checker page puts the two steps on one page.

A grammar tool changes how a sentence reads. It does not make a borrowed idea yours. You still need to cite it. See how to avoid plagiarism.

If you need to check one long paper

A thesis or dissertation will not fit in a free check. There are two ways tools charge for long documents: once per document, or by subscription. Which is cheaper depends on how many papers you will check.

• Scribbr charges per document, not by subscription. Its plagiarism checker page listed $19.95 for up to 7,499 words, $29.95 for 7,500 to 49,999 words and $39.95 for 50,000 words or more. The same page lists an AI Detector and a Sources Overview that gives each source its own colour. It also says plainly that the tool is not for you if you prefer a free plagiarism checker.
• QuillBot includes its plagiarism checker in a Premium subscription. Its plagiarism checker page says Premium lets you scan up to 25,000 words a month. We did not read its price, so check their site.
• Copyleaks is a subscription. Its pricing page listed the Personal plan at $13.99 a month, billed yearly at $167.88.
• Plagiarism Checker Plus (ours) is a subscription for longer documents. Prices are on our pricing page.

If your school gives you a checker, a long paper is exactly where to use it. Ask whether you can submit a draft.

What about Turnitin?

Turnitin is the checker many students have heard of, so it is fair to ask why it is not in the table. Turnitin’s help center has a page called Can I purchase an individual Turnitin license? It says Turnitin does not sell individual licenses or single-use subscriptions, and that it sells at the institutional level.

So a student cannot buy it alone. If your school has it, you reach it through your school. For what it does with AI writing, see does Turnitin detect AI?

How to choose

Ask these questions in this order.

1. Does my school give me a checker? If yes, start there. Ask if you may check a draft.
2. What is the word limit? Count the words in your paper. Compare that with the free limit and with the limit of the plan you are thinking of buying.
3. Do I need the sources linked? A percentage alone does not tell you what to fix. A report that links each source lets you see the original and decide whether to quote, paraphrase or cite. See how to interpret a plagiarism report.
4. Do I need an AI check too? If your course has an AI policy, a check for matching text does not cover it.
5. What happens to my text? Read each tool’s privacy policy before you upload. Look for whether your paper is stored, for how long, whether it is added to a database that later checks are compared with, and whether it is used to train AI. We can only speak for our own tool: text you check with Plagiarism Checker Plus is never used to train AI. For every other tool, read its policy and do not rely on what we or anyone else says about it.

Whatever you choose, the check is one step. How to check for plagiarism walks through the whole process, and what is plagiarism? covers what counts.

What we do not know and did not test

• Accuracy. We did not run the same papers through each tool and compare the results. We do not know which tool finds more matches or which AI detector is right more often. This page makes no claim about that.
• What each tool searches. We did not check the size or content of any tool’s sources, ours against theirs.
• What each free check really shows. We read the makers’ pages. We did not sign up for each tool and run a paper through it, so we cannot say how much detail a free result gives.
• Grammarly’s price. The plans page showed a local currency, so we did not list a price. We also do not know its word limits or whether a check needs an account, because the pages we read do not say. QuillBot’s price and Duplichecker’s paid prices are also not listed here.
• Privacy practices of other tools. We did not review their policies. Read them yourself.
• Other checkers. There are more tools than these six. Leaving one out is not a judgement about it.
• What happens after today. Makers change limits and prices. This page shows what we could read on 6 October 2026.

We also have an interest here: we would like you to try our tool. That is why the limits of our own checker are listed above, and why we do not name a winner.

Sources

Each maker’s own website, opened and read on 6 October 2026.

• Grammarly: plagiarism checker, plans and AI detector. Read.
• Copyleaks: plagiarism checker and pricing. Read.
• Duplichecker: home page. Read.
• QuillBot: plagiarism checker. Read.
• Scribbr: plagiarism checker. Read.
• Turnitin: Can I purchase an individual Turnitin license?
• Plagiarism Checker Plus: our own plagiarism checker, AI detector, grammar checker and pricing pages.