Copyleaks review: can it tell human writing from AI?

Copyleaks' scores at a glance

We rate every detector on five areas, out of 5 each. Copyleaks' scores swing from 1 to 2.5. It's easy to use and reasonably quick, but it got more texts wrong, and wrongly flagged more human writing, than any other detector we tested.

Overall: 1.5 out of 5, found by averaging the five areas and rounding to the nearest half.

• Accuracy (1/5): 71 correct calls out of 100, the lowest in our group, means it was wrong almost three times in every ten.
• False-positive rate (1/5): One human-written text in four (10 of 40) came back marked as AI, the most of any detector we tested.
• Speed (2.5/5): 27.5 seconds per text on average sat mid-pack: quicker than GPTZero, slower than Originality.ai.
• Ease of use (2.5/5): Pasting text and reading the combined AI and plagiarism report is simple; only the credits, several plans and add-on tools take time to understand.
• Value for money (1.5/5): $13.99 a month on a yearly plan looks fair on paper, but it buys the least reliable results in our group, when other detectors were more accurate for similar money.

How AI detectors work, and where Copyleaks fits

An AI detector reads a piece of writing and estimates how likely it is that a tool like ChatGPT produced it. It does this by looking for patterns, such as how predictable the word choices are and how evenly sentences are built. It never knows for sure. It's making an educated guess, which is why every detector, including Copyleaks, sometimes gets it wrong.

Copyleaks began as a plagiarism checker, which compares your text with published sources to find copied passages. It has since added AI writing detection, a detector for AI-generated images and, most recently, one for AI video. When you scan text, you get a single report covering both AI and plagiarism, with the suspicious passages highlighted. Its leadership team is led by CEO and co-founder Alon Yamin, according to its website.

The company sells to three kinds of customer: individuals, such as students and writers; schools, which connect it to their learning management system (the software teachers use to collect assignments, like Moodle); and businesses, which plug it into their own software through its API. It's one of the AI tools we cover across our AI tools section.

Checking a document with Copyleaks

Using it is straightforward once you have an account. Here's the routine we followed for each of our texts.

1. Add your content. Paste text, upload one or several files at once, or, on the Pro plan, point it at a whole website. Schools can send work straight from their learning system.

2. Spend credits. Each scan uses credits from your monthly allowance. On the Personal plan, 1,200 credits cover up to 300,000 words, or 1,200 images.

3. Read the report. You get an AI verdict and a plagiarism check side by side, with flagged sentences highlighted so you can see what triggered the result.

4. Decide what to do. This is the step that matters most. A flag is a reason to look closer, not proof, as our test shows.

What happened in our 7-day test

We tested Copyleaks from October 3 to October 9, 2026, 7 days in all. Before starting, we built a set of 100 texts where we knew exactly who, or what, wrote each one. Every detector in our group checked the same set. The full process is on our testing page.

The mix was deliberate. 40 texts were written by people, including some by writers whose first language isn't English, a group detectors are known to misjudge. 40 were written by AI. The last 20 were drafted by a chatbot and then reworked by hand, which is how many people actually use these tools.

Copyleaks made the right call on 71 texts. It correctly spotted 41 of the 60 AI or edited pieces and correctly cleared 30 of the 40 human ones. That leaves two kinds of mistake. The first is a false positive: an honest human text labelled as AI, which happened 10 times. The second is a false negative: AI writing that passed as human, which happened 19 times, often after light editing.

Those false positives matter most. If a teacher acted on every flag, one in four honest students in our set would have been wrongly accused. Copyleaks' homepage claims over 99% accuracy, adding that the figure comes from its own testing on English texts. Our mixed set, with edited and non-native writing, gave a very different answer. Each scan took 27.5 seconds on average.

Tested October 3, 2026 to October 9, 2026.

Copyleaks' features beyond AI detection

Breadth is Copyleaks' strongest argument. These are the main tools, as listed on its pricing page and homepage.

What it got right, and what it got wrong

Copyleaks pricing and plans

Copyleaks has a free way to start, two self-serve plans and a custom Enterprise option. Prices on its pricing page are shown as a monthly figure billed for the year, and Copyleaks says yearly billing saves up to 25% compared with paying monthly. We couldn't get the page to display the monthly-billing prices when we checked.

A credit is the unit Copyleaks charges in. One credit covers about 250 words of text, or one image, so the Personal plan's 1,200 credits stretch to around 300,000 words a month, roughly 300 long essays. If you run out, you can buy extra credits on the platform, and taxes may be added at checkout.

Copyleaks says you can cancel any time. We didn't find its refund rules, so if you're paying for a year up front, ask before you buy.

Prices checked on copyleaks.com on November 8, 2026.

Should you act on a Copyleaks result?

Not on its own. Our test shows why: a quarter of genuinely human texts were flagged. Writers whose first language isn't English can be especially exposed, because simpler, more predictable phrasing looks "AI-like" to detectors.

A fairer approach is to treat a flag as the start of a conversation. Ask to see drafts or the version history of the document, talk to the writer about their work, and compare it with what they've written before. If you're an editor, check the facts and sources rather than relying on a percentage.

On data safety, the homepage names four certifications, from PCI DSS for payments to GDPR for privacy. What we couldn't find was a plain explanation of how long scanned text is kept, or whether it's used to improve the detector. Schools should ask for that in writing before rolling it out.

Never treat an AI score as proof. Use it to decide where to look more closely.

Who Copyleaks is best for

Copyleaks makes the most sense when you value its range more than its raw detection accuracy.

If your real goal is writing better rather than policing writing, an AI writing assistant is a better use of the money; our list of writing assistants compares them.

Copyleaks reviews from real users

Opinion is sharply split. When we checked Trustpilot on November 8, 2026, Copyleaks had 2.7 out of 5 from 390 reviews, 79 of them from the past year. Nearly half (48%) gave 1 star, while 40% gave 5 stars, with very little in between. Trustpilot notes that Copyleaks pays for a subscription and invites its customers to leave reviews, and that it replies to 55% of negative reviews, usually within two weeks.

Satisfied users mention a thorough report, an easy process and help with their schoolwork. Unhappy users most often say the detector labelled their own writing as AI, which echoes our test, and some complain about how many credits a scan uses and about the tool not working.

Our results line up with the complaints. The one area users praise, the clarity of the report, is real, but a clear report of a wrong verdict is still wrong.

Ratings checked November 8, 2026.

Better-scoring alternatives to Copyleaks

Copyleaks finished last, so every other detector we tested did better on the same 100 texts.

Turnitin

The winner at 4 out of 5, and far fewer false accusations (4.5 for false positives). Only sold to schools and universities.

Our score 4/5 · No public price

Winston AI

Second at 3.5 out of 5, with 77 correct calls against Copyleaks' 71. Shareable reports suit publishers and teachers.

Our score 3.5/5 · Free plan; paid from $18/mo

Read review

GPTZero

2 out of 5 and ranked above Copyleaks, with 73 correct calls against its 71. Has a free plan aimed at teachers.

Our score 2/5 · Free plan; paid from $8.33/mo

Originality.ai

2 out of 5 and fourth, with fewer false positives and quicker scans. Popular with agencies checking freelance work.

Our score 2/5 · Free plan; paid from $14.95/mo

Each alternative's price was taken from its own website when we reviewed it.