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Side-by-side comparison · Writing & Translation

GPTZero vs Originality.ai vs QuillBot

Everything that matters when choosing between them, in one place: our rating, what each can do, what they cost, and the trade-offs.

Best overall

GPTZero

4.2

From $0

Originality.ai

4.1

From $14.95/mo

QuillBot

4.1

From $19.95/mo

Comparing 3 tools, the maximum.

At a glance

Best overall

Pick it if: Teachers, editors and business owners who want a second opinion on whether writing they've been handed came from AI.

Pick it if: Publishers, content agencies, SEO teams and businesses that commission written content and want to check it before publishing.

Easiest to use

Pick it if: Students, non-native English writers and anyone who wants a paragraph cleaned up or reworded in one click.

Overview

AttributeGPTZeroOriginality.aiQuillBot
In one lineChecks whether text was written by AI, with plagiarism and citation checks too.Checks content for AI writing, plagiarism and factual errors before you publish it.Rewords, fixes grammar and summarises text, with an AI checker and humaniser built in.
Pricing modelFreemiumFreemiumFreemium
Starting price$0$14.95/mo$19.95/mo
Free plan Yes Yes Yes
Works with Claude Code Yes Yes No

Rating breakdown

Our scores out of 5. The higher bar in each row is highlighted.

AttributeGPTZeroOriginality.aiQuillBot
Overall rating4.2Winner4.14.1
Ease of useHow quickly someone non-technical gets value from it.
4.5
4.0
5.0
FeaturesHow completely it covers its own job, and how well the pieces fit together.
4.5
4.5
4.0
Output qualityHow good the results are before you fix them.
3.5
3.5
3.5
Value for moneyWhat you get for the price, including the free plan.
4.0
4.0
4.0
Speed & reliabilityHow fast it is and how often it falls over.
4.5
4.5
4.0

Feature comparison

A tick means it does this today. A dash means we haven't checked.

AttributeGPTZeroOriginality.aiQuillBot
Access & platform
Free plan Yes Yes Yes
Mobile app No– Yes
Desktop app–– Yes
Browser extension Yes Yes Yes
API access Yes Yes No
Teams & business
Team workspace Yes Yes Yes
Enterprise plan or SSO Yes Yes–
Connects to other apps Yes Yes Yes
Open source or self-hosted No No No
AI abilities
Works with your files Yes Yes Yes
Understands images–– No
Makes images No No–
Makes video No No No
Writes code No No No
Runs agents or automations No No No
Learns your brand or style–– Yes
Works in many languages Yes– Yes
Capabilities score8/ 177/ 179/ 17

Pricing

Plans as listed on each vendor's site when we last checked. Confirm before you buy.

AttributeGPTZeroOriginality.aiQuillBot
Plans

Free

$0

Checking the odd document.

Free

Free

Checking the odd article.

Free

Free

Odd sentences and quick grammar checks.

PremiumOur pick

$23.99/mo, or $12.99/mo billed yearly

Teachers and editors checking work every week.

ProOur pick

$14.95/mo, or $12.95/mo billed yearly

Agencies and site owners checking content every week.

PremiumOur pick

$19.95/mo, or $99.95/yr ($8.33/mo)

Anyone rewording or checking text most weeks.

Professional

$45.99/mo, or $24.99/mo billed yearly

Agencies and heavy users scanning lots of files.

Enterprise

$179/mo, or $136.58/mo billed yearly

Publishers and large content teams.

Team

Per seat, billed yearly

Schools and companies buying for a group.

Team

Professional price per seat, 2 seats minimum

Schools and businesses buying for a group.

Which plan to pickStart on Free. If you check more than a few documents a week, Premium on yearly billing is the sweet spot. Professional only makes sense if you scan big batches of files.Pro is enough for most agencies and site owners. An AI and plagiarism check together uses two credits per 100 words, so budget about 100,000 words of checked content a month. Go Enterprise only if you need the API or very high volume.Stay on Free if you only reword the odd sentence. If you use it every week, the yearly Premium plan is far cheaper than paying monthly, but set a reminder before it renews because refunds after renewal are hard to get.

Key features

AttributeGPTZeroOriginality.aiQuillBot
Standout features
  • AI detection
  • Plagiarism check
  • Writing replay
  • Citation and hallucination check
  • Batch scans
  • API and school integrations
  • AI detection
  • Plagiarism checker
  • Fact checker
  • Bulk and site scans
  • Writing replay
  • API
  • Paraphraser
  • Grammar checker
  • Summariser
  • AI detector and humaniser
  • Plagiarism checker and citations
  • Works where you write

Pros and cons

AttributeGPTZeroOriginality.aiQuillBot
Pros
  • Clear sentence-level highlights, so you see exactly what looks AI-written
  • Generous free plan for occasional checks
  • Writing replay gives honest writers a way to prove their work
  • Flags made-up citations, which most detectors don't
  • API and batch scans for larger volumes
  • AI, plagiarism, facts and readability in one scan
  • Cheap for the volume on Pro
  • Bulk and whole-site scanning
  • Writing replay gives honest writers a way to prove their work
  • API for content teams
  • No learning curve: paste, pick a mode, click
  • Yearly Premium is cheap next to Grammarly or a chat assistant
  • Many rewrite styles, including ones you define yourself
  • Grammar, summaries, citations and plagiarism checks in one subscription
  • Works inside Chrome and Word so you stay in your document
Cons
  • False positives happen, and short or formal writing gets flagged more often
  • Edited or reworded AI text can get past it
  • The best scan and plagiarism checks need a paid plan
  • Mostly designed around schools, so some features won't matter to a business
  • False positives are a recurring complaint, and independent tests find more than the vendor claims
  • Monthly credits expire if you don't use them
  • API is only on the expensive Enterprise plan
  • A score can sour a client or writer relationship if treated as proof
  • Free plan caps paraphrasing at 125 words per go and hides most modes
  • Reworded text can change your meaning or read awkwardly, so every rewrite needs checking
  • AI detector and humaniser are inconsistent, and the humaniser often still gets flagged by school checkers
  • Complaints about surprise annual renewals, refused refunds and constant upgrade pop-ups on the free plan
  • Owned by Learneo (Course Hero), and some users object to its data and privacy terms

Who each one is for

AttributeGPTZeroOriginality.aiQuillBot
Best for
  • Checking essays and assignments for AI writing
  • Screening freelance or agency content
  • Spotting made-up citations in reports
  • Showing you wrote a document yourself
  • Checking freelance and agency content
  • AI and plagiarism checks in one scan
  • Fact-checking articles before they go live
  • Bulk scanning a website
  • Proving a writer wrote their own draft
  • Rewording a sentence or paragraph
  • Grammar and spelling fixes
  • Summarising articles and readings
  • Writing in a second language
  • Making formal writing simpler
You'll find it used by
  • Teachers
  • Editors
  • Content agencies
  • Recruiters
  • Students
  • Content agencies
  • Publishers
  • SEO teams
  • Marketing managers
  • Website buyers
  • Students
  • Non-native English writers
  • Academics
  • Freelance writers
  • Office staff

Questions people ask

Which is better, GPTZero, Originality.ai or QuillBot?

GPTZero scores highest overall in our ratings (GPTZero 4.2/5, Originality.ai 4.1/5 and QuillBot 4.1/5). GPTZero is best for checking essays and assignments for AI writing and screening freelance or agency content. Originality.ai is best for checking freelance and agency content and AI and plagiarism checks in one scan. QuillBot is best for rewording a sentence or paragraph and grammar and spelling fixes.

Which is cheaper, GPTZero, Originality.ai or QuillBot?

GPTZero: There's a free plan, and paid plans start at $0. Originality.ai: There's a free plan, and paid plans start at $14.95/mo. QuillBot: There's a free plan, and paid plans start at $19.95/mo.

Which is easier to use, GPTZero, Originality.ai or QuillBot?

QuillBot rates highest for ease of use in our scores. Students, non-native English writers and anyone who wants a paragraph cleaned up or reworded in one click.

How we compare

Ratings are our own, from using each tool, across ease of use, features, output quality, value for money, speed & reliability.

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