Plagiarism Checker Plus vs Copyleaks

The short answer

Both tools check for plagiarism and for likely AI writing, and both show where a match came from. Copyleaks is the larger platform: it lists LMS integrations, 100+ languages and enterprise options. Plagiarism Checker Plus is a smaller self-serve tool with a first check that needs no account and a lower listed starting price.

Head-to-head table

Our column comes from our own product and pricing page. The Copyleaks column comes from the pages linked in the sources. Prices are listed US dollar prices on 10 October 2026.

Prices and limits change. Read both pricing pages on the day you buy.

Free use and sign-up

The two tools give free access in different places.

• For a plagiarism check, ours runs once without an account, up to 1,000 words. Copyleaks’ plagiarism checker page says you can try it free by registering for a Copyleaks account.
• For an AI check, Copyleaks is the more generous of the two without an account. Its AI detector page says you can scan up to 25,000 characters without logging in. Ours gives one free AI check of up to 1,000 words, then asks for a free account.
• With a free account, ours includes 3,000 words a month. Copyleaks says new users get a limited number of free credits. We could not find the number.

If all you need is a quick AI reading of a long passage with no sign-up, Copyleaks’ free box takes more text than ours.

What the reports show

Plagiarism

Both reports show the matching text and where it came from. Copyleaks’ page says its report sorts matches into identical text, minor changes and paraphrased text, and that the report can be customized, downloaded and shared. It also lists features we do not have: cross-language plagiarism detection, source code plagiarism detection and scheduled recurring scans.

Our report links every matching passage to its source, so you can open the original and decide whether to quote, paraphrase or cite. We have no database of other students’ submitted papers. Copyleaks describes a Shared Data Hub, a library of user-submitted documents, on its pricing page. Our guide on how to interpret a plagiarism report applies to either tool.

AI detection

Our AI detector gives an overall score and a likelihood for every sentence. Copyleaks shows what percentage of the text is likely AI-generated, with sentence-by-sentence detail on an account. Paid Copyleaks plans add AI Logic, which Copyleaks says shows why text was flagged. Copyleaks also lists an AI image detector. We do not check images.

On accuracy, the two companies take different positions. Copyleaks publishes figures: over 99% accuracy and a 0.03% false positive rate, with a footnote on its plagiarism checker page that the accuracy rating is based on internal testing of English language datasets. We publish no accuracy figure. Either way, an AI score is a likelihood, not proof. See how AI detectors work.

Price for one person

Copyleaks counts in credits. Its pricing page says one credit covers up to 250 words or one image. We count in words: one word checked is one word used, for each tool you run. The plans are not like for like. Copyleaks’ Personal plan includes AI image detection and its wider language coverage. Our paid plans add longer documents, folders and, on Team and Enterprise, API access. Our full list is on the pricing page.

When Copyleaks is the better choice

Choose Copyleaks, not us, in these cases.

• You need checking inside an LMS. Copyleaks lists Canvas, Moodle, D2L Brightspace, Schoology, Sakai, Edsby and Blackboard, with grades and feedback synced. We have no LMS integration.
• You are buying for a whole school or company. Copyleaks has Education and Enterprise plans with analytics at student, course and institution level, multi-admin permissions, onboarding and training. Its Enterprise plan lists on-premises or private cloud hosting.
• You write or check work in a language other than English. Copyleaks lists AI detection in 30+ languages and plagiarism detection in 100+. Our web app and reports are in English.
• You need to check source code or images. Copyleaks lists source code plagiarism detection and an AI image detector. We check text only.
• You want to compare against documents other users have submitted. Copyleaks describes a Shared Data Hub and, for institutions, private cloud storage built for internal comparisons. We have no database of submitted student papers.
• You use Edge or Firefox. Copyleaks’ pricing page lists its extension for Chrome, Edge and Firefox.
• You want a long AI check with no sign-up. Up to 25,000 characters, against our 1,000 words.
• You need formal security certifications. Copyleaks lists SOC 2, SOC 3, GDPR and PCI DSS on its API page.

When Plagiarism Checker Plus is the better choice

Our tool may suit you better in these cases. This is our view of our own product.

• You want a plagiarism check right now, with no account. The first check is free up to 1,000 words. Copyleaks’ page says its plagiarism checker is tried by registering.
• You are one student on a small budget. Our Student plan is listed at $4.99 a month for 60,000 words. Copyleaks’ lowest listed plan is $16.99 a month.
• You want citations in the same place. Our citation generator covers APA, MLA, Chicago, Harvard, IEEE, AMA and ACS. We did not find a citation generator on the Copyleaks pages we read.
• You want a steady monthly free allowance. A free account includes 3,000 words every month. Copyleaks describes a limited number of free credits for new users.
• You work in Google Docs or Chrome and write in English. We have a Google Docs add-on and a Chrome extension. Copyleaks has both of these too, so this is a match, not an advantage.

That list is shorter than the one above. Copyleaks is a broader product. Ours is narrower and costs less to start.

When neither is the answer

If your school gives you a checker in the place where you hand in work, use that one first. It is the report your work is judged with. Our tool and Copyleaks’ individual plans each search their own sources, so neither will show the same result as your school’s system.

A checker also cannot tell you whether a borrowed idea is cited correctly. That part is on you. See how to avoid plagiarism and how to check for plagiarism.

What we do not know and did not test

• Accuracy. We did not run the same documents through both tools. We do not know which finds more matches or which AI detector is right more often.
• Copyleaks’ free credits. The number is not on the pages we read.
• Copyleaks’ Education, Enterprise and API prices. They are quoted by its sales team.
• Whether Copyleaks has a citation tool. We did not find one on the pages we read. That is not proof it has none.
• The size of Copyleaks’ sources. We repeated what its page says and did not check it.
• Copyleaks’ privacy practices. We did not review its policy. Read it before you upload.
• What happens after today. This page shows what we could read on 10 October 2026.

Sources

Copyleaks’ own website, read on 10 October 2026.

• Copyleaks pricing: plans, prices, credits, languages, extension, Google Docs add-on, LMS list, Education and Enterprise features.
• Copyleaks plagiarism checker: sources searched, report links, similarity types, free trial by registering.
• Copyleaks AI detector: free limit without logging in, sentence detail, its accuracy and false positive figures.
• Copyleaks API and grammar checker.
• Plagiarism Checker Plus: our own plagiarism checker, AI detector, grammar checker, citation generator, API and pricing pages.