QuillBot Review (2026): Great Paraphraser, Shaky AI Detector

Few writing tools sell both the lock and the key. This QuillBot review looks at an app that offers an AI humanizer and an AI detector under the same login.

You will see the name written as QuillBot, Quillbot, Quill Bot or even quilbot. Whatever the spelling, the company says more than 35 million people use it.

Therefore the testing behind this QuillBot review followed three questions. First, what does the free plan really allow? Second, what does Premium cost today? Finally, can you trust the detector and the humanizer with schoolwork?

So, what is QuillBot? It started in 2017 as a paraphrasing tool that rewrites sentences while keeping the meaning. Since then it has grown into a full writing suite.

Today the sidebar lists a Paraphraser, Grammar Checker, AI Detector, Plagiarism Checker and AI Humanizer. In addition, it offers AI Chat, an AI image generator, a translator, a summarizer and a citation generator. A document editor called Flow ties those tools together.

Course Hero bought the company in August 2021. As a result, QuillBot now sits inside Learneo, the group that also owns Course Hero, Symbolab and LitCharts.

Students make up the core audience, and the product shows it. Citations, summaries and plagiarism checks all point at essays and research papers.

However, non-native English speakers get just as much from it. The paraphraser and grammar checker help a rough draft sound fluent. Meanwhile, bloggers and marketers use it to rework copy quickly.

It is a weaker fit for professional editors. Likewise, anyone who needs proof that a text is human will find the detector too shaky for that job.

Four tools do most of the work. Each one has a free tier, and each one opens up fully with Premium.

The QuillBot paraphrasing tool is still the main draw. You paste text on the left, pick a mode and press Paraphrase. The rewrite then appears on the right.

Free users get two modes and a limit of 125 words per run. Premium unlocks every mode, including Fluency, Formal and Humanize. In addition, a synonyms slider controls how far the wording moves from your original.

The QuillBot AI detector asks for at least 40 words, pasted or uploaded as a document. According to the page, it is trained on output from GPT-6, Gemini, Claude and Llama.

It scores text sentence by sentence rather than as one block. Because of this, it can point at the specific lines it thinks a model wrote. Free access is limited, while Premium removes the cap.

The QuillBot AI humanizer takes stiff, machine-sounding text and loosens the rhythm. It works like the paraphraser, with a single Humanize button and panels for history, statistics and tone.

On the free plan you can humanize up to 125 words with limited usage. Premium gives full access plus the history and insight panels. Still, QuillBot presents it as a way to improve flow, not as a way to beat detectors.

The grammar checker fixes basic errors for free and works in six languages. Premium adds advanced recommendations and tone insights.

The summarizer handles 1,200 words on the free plan and 6,000 with Premium. Furthermore, the citation generator builds references in common academic styles. Extensions for Chrome and Edge, a Word add-in, a macOS app and mobile keyboards carry those tools into other apps.

In practice, the paraphraser is the strongest part. It keeps the meaning in most short passages, and the modes give real control over tone. However, longer rewrites sometimes come back awkward or repetitive, so you still need to read every line.

The grammar checker is fine for typos and agreement errors. Yet it is lighter than Grammarly on tone and clarity feedback, which other reviewers also point out.

Is the QuillBot AI detector accurate? Only partly. A GPTZero write-up of journalist tests puts it at roughly 80% accuracy. It also says the detector leans toward calling human writing AI.

Keep in mind that GPTZero sells a rival detector, so it has a stake in that result. Even so, a one in five miss rate is too high for grading or hiring decisions. This QuillBot review treats the score as a hint, never as proof.

Can Turnitin detect QuillBot? Sometimes. Published tests disagree, and a Turnitin staff member has acknowledged reports of QuillBot output being flagged wrongly. As a result, paraphrasing your own draft can still trigger an AI flag.

There is one paid plan for individuals and a separate plan for teams. Every price in this QuillBot review was read on October 5, 2026, and one detail needs a warning.

Is QuillBot free? Yes, and the free plan is usable for short jobs. You can paraphrase 125 words at a time in two modes, fix basic grammar and summarize 1,200 words.

However, the annual price depends on where you check it. From a European connection the official page showed $4.17 a month, billed annually. Meanwhile, three US reviews from 2026 quote $8.33 a month for the same plan. Therefore confirm the figure at checkout before you pay.

Searches for a QuillBot discount or promo code are common. We found no official code on the pricing page. Instead, the annual plan is the discount, and the page also lets you pause a subscription.

Most buyers compare these two first. Grammarly is the stronger proofreader, with deeper feedback on tone, clarity and style.

QuillBot, on the other hand, wins on rewriting. Its paraphraser has more modes, and the same plan adds a summarizer, citations and a humanizer.

So pick Grammarly if you mostly polish your own writing. Choose QuillBot if you often rework, shorten or cite text and want a lower annual bill.

Is QuillBot legit? Yes. It is an established company with a large owner, published plans and apps in the official stores. It also runs a public affiliate program.

Is QuillBot safe? For everyday drafts, it is as safe as any mainstream cloud writing tool. Even so, your text is processed on its servers, so avoid pasting confidential or client material.

The larger risk is academic. Many schools count paraphrased or humanized AI text as misconduct. Therefore check your policy first, and keep your drafts as evidence of your own work.

Grammarly remains the benchmark for grammar, tone and clarity checks. It also works inside more desktop apps.

However, it costs more per year and its rewriting tools are narrower. Pick it when proofreading is the main job.

Undetectable AI is a dedicated humanizer with its own detector built in. It focuses on one task instead of a full writing suite.

Consider it if humanizing is all you need and you want more control over that single step.

HIX AI wraps a humanizer inside an agent workspace for research, slides and media. Our HIX AI review covers its credits and test results.

It suits people who want one subscription for many AI tasks rather than a writing toolkit.

Pros

• Paraphrasing tool with several modes and a synonyms slider that controls how much changes
• One subscription covers paraphrasing, grammar, summaries, citations, plagiarism checks and a humanizer
• A usable free plan with 125 words per paraphrase and 1,200 words per summary
• Extensions for Chrome and Edge, a Word add-in, a macOS app and mobile keyboards
• The annual plan costs far less per month than monthly billing

Cons

• The AI detector sits near 80% accuracy in journalist tests and can flag human writing
• The annual price shown differs by region, so the figure needs confirming at checkout
• The free plan stops at 125 words and two paraphrasing modes
• Longer rewrites can turn awkward or repetitive and need manual editing
• The grammar checker gives lighter tone and clarity feedback than Grammarly

For rewriting, yes. QuillBot is still one of the best paraphrasing tools you can buy, and the bundle around it is generous for the annual price.

For detection, be careful. The detector is a useful second opinion, but it is wrong often enough that no grade or job should rest on it. Similarly, the humanizer improves flow without making AI text invisible.

The short answer from this QuillBot review: start on the free plan, and pay yearly only if you rewrite or summarize every week. One company now sells the tool that disguises AI text and the tool that hunts it. In the end, the safest words are the ones you can explain writing yourself.

If humanizing is the goal, compare every serious option in our guide to the best AI humanizer tools, with plans and limits side by side.

In addition, the best AI writing tools collection covers drafting assistants, and our Jenni AI review looks at a writer built for research papers.