Skip to content

Side-by-side comparison · Writing & Translation

GPTZero vs Grammarly vs Originality.ai

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

GPTZero

4.2

From $0

Best overall

Grammarly

4.3

From $12/member/mo

Originality.ai

4.1

From $14.95/mo

Comparing 3 tools, the maximum.

At a glance

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

Best overallEasiest to use

Pick it if: Anyone who writes emails, documents and messages at work and wants mistakes caught and tone checked before they hit send.

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

Overview

AttributeGPTZeroGrammarlyOriginality.ai
In one lineChecks whether text was written by AI, with plagiarism and citation checks too.Fixes grammar, clarity and tone in your writing, wherever you type.Checks content for AI writing, plagiarism and factual errors before you publish it.
Pricing modelFreemiumFreemiumFreemium
Starting price$0$12/member/mo$14.95/mo
Free plan Yes Yes Yes
Works with Claude Code Yes No Yes

Rating breakdown

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

AttributeGPTZeroGrammarlyOriginality.ai
Overall rating4.24.3Winner4.1
Ease of useHow quickly someone non-technical gets value from it.
4.5
5.0
4.0
FeaturesHow completely it covers its own job, and how well the pieces fit together.
4.5
4.5
4.5
Output qualityHow good the results are before you fix them.
3.5
4.0
3.5
Value for moneyWhat you get for the price, including the free plan.
4.0
3.5
4.0
Speed & reliabilityHow fast it is and how often it falls over.
4.5
4.5
4.5

Feature comparison

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

AttributeGPTZeroGrammarlyOriginality.ai
Access & platform
Free plan Yes Yes Yes
Mobile app No Yes–
Desktop app– Yes–
Browser extension Yes Yes Yes
API access Yes– Yes
Teams & business
Team workspace Yes Yes Yes
Enterprise plan or SSO Yes 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
Understands images–––
Makes images No No No
Makes video No No No
Writes code No No No
Runs agents or automations No– No
Learns your brand or style– Yes–
Works in many languages Yes––
Capabilities score8/ 178/ 177/ 17

Pricing

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

AttributeGPTZeroGrammarlyOriginality.ai
Plans

Free

$0

Checking the odd document.

Free

Free

Basic spelling and grammar checks.

Free

Free

Checking the odd article.

PremiumOur pick

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

Teachers and editors checking work every week.

ProOur pick

$12/member/mo billed yearly, or about $30 monthly

Anyone who writes a lot at work, alone or in a team.

ProOur pick

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

Agencies and site owners checking content every week.

Professional

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

Agencies and heavy users scanning lots of files.

Enterprise

Custom

Large organisations with security needs.

Enterprise

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

Publishers and large content teams.

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.Free is enough for typo-catching. If you write for clients or customers every day, Pro on yearly billing is good value; paying monthly costs more than double.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.

Key features

AttributeGPTZeroGrammarlyOriginality.ai
Standout features
  • AI detection
  • Plagiarism check
  • Writing replay
  • Citation and hallucination check
  • Batch scans
  • API and school integrations
  • Live checking everywhere
  • Clarity and rewrites
  • Tone detection
  • AI writing assistant
  • Plagiarism and AI detection
  • Team style guides
  • AI detection
  • Plagiarism checker
  • Fact checker
  • Bulk and site scans
  • Writing replay
  • API

Pros and cons

AttributeGPTZeroGrammarlyOriginality.ai
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
  • Works live in almost every app you type in
  • Free plan is useful for everyday spelling and grammar
  • Tone feedback helps with tricky messages
  • Team style guides keep company writing consistent
  • Yearly Pro price is reasonable for daily use
  • 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
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
  • Free plan no longer includes sentence rewrites and caps AI prompts at 100 a month
  • Monthly billing costs more than double the yearly rate
  • Accepting every suggestion can strip your own voice
  • Strongest in English only
  • Withdrew its "Expert Review" feature in 2026 after a lawsuit over using authors' identities
  • 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

Who each one is for

AttributeGPTZeroGrammarlyOriginality.ai
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
  • Proofreading emails and documents as you type
  • Checking tone before a tricky message goes out
  • Writing at work in English as a second language
  • Keeping a team's writing style consistent
  • Plagiarism checks on content
  • 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
You'll find it used by
  • Teachers
  • Editors
  • Content agencies
  • Recruiters
  • Students
  • Office staff
  • Sales and support teams
  • Non-native English writers
  • Students
  • Marketers
  • Content agencies
  • Publishers
  • SEO teams
  • Marketing managers
  • Website buyers

Questions people ask

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

Grammarly scores highest overall in our ratings (GPTZero 4.2/5, Grammarly 4.3/5 and Originality.ai 4.1/5). GPTZero is best for checking essays and assignments for AI writing and screening freelance or agency content. Grammarly is best for proofreading emails and documents as you type and checking tone before a tricky message goes out. Originality.ai is best for checking freelance and agency content and AI and plagiarism checks in one scan.

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

GPTZero: There's a free plan, and paid plans start at $0. Grammarly: There's a free plan, and paid plans start at $12/member/mo. Originality.ai: There's a free plan, and paid plans start at $14.95/mo.

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

Grammarly rates highest for ease of use in our scores. Anyone who writes emails, documents and messages at work and wants mistakes caught and tone checked before they hit send.

How we compare

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

Swap in another tool

More tools from Writing & Translation in the library.