# Copyleaks Alternatives 2027: 16 Paid, Free & Open-Source

Source: https://zekaiwork.com/alternatives/copyleaks/
Prices checked: 2026-11-13 (Zekai Price Ledger)

The best Copyleaks alternatives in 2027 are Originality.ai (best overall, $12.95/mo billed yearly), GPTZero (best free plan: 10,000 words a month) and SlopTotal (best open source, MIT). Copyleaks itself starts at $13.99/mo billed yearly. Zekai checked these prices on vendor pages on 13 Nov 2026; 13 more are compared below, including 4 with a free plan and 6 open source.

| Tool | Type | Starting price | Free plan limit | Licence | Best for | Price checked | Links |
|---|---|---|---|---|---|---|---|
| Copyleaks (the tool being replaced) | — | $13.99/mo billed yearly | 25,000 characters per free scan; no free plan on pricing page | — | — | 2026-11-12 | [pricing](https://copyleaks.com/pricing) |
| GPTZero | Free plan + paid | $12.99/mo billed yearly | 10,000 words a month, 1 advanced scan | — | Teachers wanting sentence highlights and model detection | 2026-11-12 | [site](https://gptzero.me) [pricing](https://gptzero.me/pricing) [Zekai page](https://zekaiwork.com/ai-tools/gptzero/) |
| Originality.ai | Free plan + paid | $12.95/mo billed yearly | 10K words (100 credits) one time; comparison table says 60 credits renewing daily | — | Bulk content checks for publishers and agencies | 2026-11-12 | [site](https://originality.ai) [pricing](https://originality.ai/pricing) [Zekai page](https://zekaiwork.com/ai-tools/originality-ai/) |
| Winston AI | Free plan + paid | $10/mo billed yearly | 2,000 credits, 14-day trial | — | Detecting AI text, images and deepfakes together | 2026-11-12 | [site](https://gowinston.ai) [pricing](https://gowinston.ai/pricing/) [Zekai page](https://zekaiwork.com/ai-tools/winston-ai/) |
| ZeroGPT | Free plan + paid | $8.99/mo billed yearly | 15,000 characters per AI detection | — | Quick free AI text checks with batch upload | 2026-11-12 | [site](https://www.zerogpt.com) [pricing](https://www.zerogpt.com/pricing) [Zekai page](https://zekaiwork.com/ai-tools/zerogpt/) |
| Quetext | Free plan + paid | $14.99/mo | AI detector up to 1,000 words; plagiarism checker up to 1,000 words | — | Plagiarism checker and AI detector bundle | 2026-11-12 | [site](https://www.quetext.com) [pricing](https://www.quetext.com/pricing) [Zekai page](https://zekaiwork.com/ai-tools/quetext/) |
| Isgen | Paid | $8/mo billed yearly | No free plan | — | Low-cost academic detector with plagiarism check | 2026-11-12 | [site](https://isgen.ai) [pricing](https://isgen.ai/pricing) [Zekai page](https://zekaiwork.com/ai-tools/isgen/) |
| PlagiarismCheck.org | Paid | Not checked | No free plan | — | Institutional plagiarism and AI checks | 2026-11-12 | [site](https://plagiarismcheck.org) [pricing](https://plagiarismcheck.org/pricing/) [Zekai page](https://zekaiwork.com/ai-tools/plagiarismcheckorg/) |
| Scribbr | Free | Free plan; paid price not published | Unlimited free AI checks, no sign-up; word cap not stated | — | Students wanting a no-sign-up free check | 2026-11-12 | [site](https://www.scribbr.com) [pricing](https://www.scribbr.com/ai-detector/) [Zekai page](https://zekaiwork.com/ai-tools/scribbr/) |
| Turnitin | Paid | Not checked | No free plan | — | Institution-wide similarity and AI writing checks | 2026-11-12 | [site](https://www.turnitin.com) [pricing](https://turnitin.com/solutions/ai-writing) [Zekai page](https://zekaiwork.com/ai-tools/turnitin/) |
| SlopTotal | Open source | Free (self-hosted) | No limit (self-hosted) | MIT | Self-hosted multi-engine AI text detector | 2026-11-13 | [site](https://sloptotal.com) [code](https://github.com/pablocaeg/sloptotal) [Zekai page](https://zekaiwork.com/free-open-source/sloptotal/) |
| Binoculars | Open source | Free (self-hosted) | No limit (self-hosted) | BSD-3-Clause | Research-grade zero-shot detection you run yourself | 2026-11-13 | [site](https://github.com/ahans30/Binoculars) [code](https://github.com/ahans30/Binoculars) [Zekai page](https://zekaiwork.com/free-open-source/binoculars/) |
| Fast-DetectGPT | Open source | Free (self-hosted) | No limit (self-hosted) | MIT | Zero-shot detection from an ICLR 2024 paper | 2026-11-13 | [site](https://fastdetect.net/) [code](https://github.com/baoguangsheng/fast-detect-gpt) [Zekai page](https://zekaiwork.com/free-open-source/fast-detect-gpt/) |
| Open Detector | Open source | Free (self-hosted) | No limit (self-hosted) | MIT | Academic-paper AI detection with a small model | 2026-11-13 | [site](https://github.com/Imalwayshere/Open-Detector) [code](https://github.com/Imalwayshere/Open-Detector) [Zekai page](https://zekaiwork.com/free-open-source/open-detector/) |
| SynthID Text | Open source | Free (self-hosted) | No limit (self-hosted) | Apache-2.0 | Watermark detection for text you generate | 2026-11-13 | [site](https://github.com/google-deepmind/synthid-text) [code](https://github.com/google-deepmind/synthid-text) [Zekai page](https://zekaiwork.com/free-open-source/synthid-text/) |
| Dolos | Open source | Free (self-hosted) | No limit (self-hosted) | MIT | Source-code plagiarism checks in programming courses | 2026-11-13 | [site](https://dolos.ugent.be) [code](https://github.com/dodona-edu/dolos) [Zekai page](https://zekaiwork.com/free-open-source/dolos/) |
| JPlag | Open source | Free (self-hosted) | No limit (self-hosted) | GPL-3.0 | Source-code plagiarism checks across many languages | 2026-11-13 | [site](https://github.com/jplag/JPlag) [code](https://github.com/jplag/JPlag) [Zekai page](https://zekaiwork.com/free-open-source/jplag/) |

## How each alternative compares with Copyleaks

- **GPTZero** (Free plan + paid, $12.99/mo billed yearly, checked 2026-11-12): Free plan allows 10,000 words a month; Premium lists 300,000 words a month, multi-model detection (Gemini, Claude, LLaMa), 50,000 characters per scan and 50-file batch upload, billed per word not per credit. Switch if you want a recurring free word quota and a detector that names the model family and highlights mixed AI and human sentences. Stay with Copyleaks if you need image detection, whole-site sitemap scans or a 25-seat plan in one credit-based account.
- **Originality.ai** (Free plan + paid, $12.95/mo billed yearly, checked 2026-11-12): Pro gives 200K words (2K credits) a month with 30-day scan history, bulk scan, shareable reports and a Chrome extension; Copyleaks Personal gives 100 credits of 250 words each, about 25,000 words. Switch if you audit freelance copy for a publisher and want 200K words a month with team seats and scan history. Stay with Copyleaks if you need plagiarism checks across 30 languages plus image detection from one credit pool.
- **Winston AI** (Free plan + paid, $10/mo billed yearly, checked 2026-11-12): Credit-based: Essential gives 100,000 credits a month and covers AI image and deepfake detection, OCR for scans and handwriting, plagiarism checks and shareable PDF reports; Advanced adds 5 team members. Switch if you want text, image and deepfake detection together and a cheaper entry plan than credit packs. Stay with Copyleaks if you need document-level plagiarism checks and cross-language matching on larger teams.
- **ZeroGPT** (Free plan + paid, $8.99/mo billed yearly, checked 2026-11-12): Free forever with 15,000 characters per detection and no card; Pro at $8.99 a month billed yearly allows 100,000 characters, 50 batch files and a 750-word one-time plagiarism check. Switch if you want a free no-card checker plus a low-cost Pro for occasional AI checks rather than credit billing. Stay with Copyleaks if you need institution-grade plagiarism reports and LMS integrations such as Canvas and Moodle.
- **Quetext** (Free plan + paid, $14.99/mo, checked 2026-11-12): Essential bundles a plagiarism checker and AI detector on 100k words a month, plus a humanizer, summarizer, API access and 20-file bulk upload; the free AI detector stops at 1,000 words. Switch if you want a plainer plagiarism-first tool with a humanizer and summarizer bundled in at a similar monthly price. Stay with Copyleaks if you scan by credit with image checks and website crawling by sitemap.
- **Isgen** (Paid, $8/mo billed yearly, checked 2026-11-12): Academic plan is $8 a month billed yearly ($14 monthly) for 350,000 detection words a month, phrase-level analysis, a plagiarism checker, 60,000 characters per submission and 15 days of history. Switch if you want a cheaper yearly plan with 350,000 detection words and no credit counting. Stay with Copyleaks if you want Copyleaks' multi-language plagiarism matching and sitemap-based website scans.
- **PlagiarismCheck.org** (Paid, Not checked): Sells Advanced and Pro organisation plans by quote only; the pricing page lists a Google Docs add-on, LMS integrations and onboarding, and Pro offers any interface language. Switch if you are an institution that wants a quoted plan with LMS integrations and a Google Docs add-on. Stay with Copyleaks if you want published self-serve prices and a credit-based personal plan you can start today.
- **Scribbr** (Free, Free plan; paid price not published): Advertises unlimited free AI checks with no sign-up and a separate Premium AI Detector; the page states no word cap and no published Premium price. Switch if you only need quick free AI-text checks without an account and no plagiarism database. Stay with Copyleaks if you need document-level plagiarism matching against web and publisher sources.
- **Turnitin** (Paid, Not checked): Sold to institutions through sales with LMS integration; its AI writing detection is described as available with Originality, and no price or free tier is published. Switch if your institution already licenses it and needs LMS-integrated similarity and AI reports. Stay with Copyleaks if you buy as an individual and want a published self-serve price per month.
- **SlopTotal** (Open source, Free (self-hosted)): Runs 23 detection engines, including Binoculars and Fast-DetectGPT, on your own CPU and returns one calibrated score with per-engine votes, file and URL scanning, and a JSON API. Switch if you want a self-hosted detector with a web page and API that runs on a CPU. Stay with Copyleaks if you need a vendor-supported service with accounts, teams and an uptime commitment.
- **Binoculars** (Open source, Free (self-hosted)): Zero-shot detector needing no training data; it scores text with two Falcon-7B models locally and returns a score, without sentence highlighting or a web dashboard. Switch if you want self-hosted detection with no per-credit billing and can run 7B models. Stay with Copyleaks if you want plagiarism matching and reports, which a model-scoring script lacks.
- **Fast-DetectGPT** (Open source, Free (self-hosted)): ICLR 2024 zero-shot method using conditional probability curvature; the README reports 0.9887 AUROC on five-model generations and ships a local script, with no dashboard or upload. Switch if you want a peer-reviewed scoring method you can run on your own GPU. Stay with Copyleaks if you want to paste text into a web page and get a result without installing models.
- **Open Detector** (Open source, Free (self-hosted)): BERT-base classifier trained for academic papers; the README claims 99.57% accuracy on its own dataset and says it is stylometric only. It is a model and script, not a web app. Switch if you check academic papers and want an MIT-licensed BERT model you can run locally. Stay with Copyleaks if you check blog posts, emails or marketing copy rather than academic writing.
- **SynthID Text** (Open source, Free (self-hosted)): Google DeepMind reference code that detects only text carrying its SynthID watermark; the frequentist detector gives a binomial p-value for a key, so it cannot flag unwatermarked ChatGPT or Claude output. Switch if you generate text with your own model and want to watermark it for later verification. Stay with Copyleaks if you need to check ChatGPT, Claude or Gemini text that carries no watermark you control.
- **Dolos** (Open source, Free (self-hosted)): Compares source-code submissions with each other and shows similarity scores and a side-by-side view; it checks code only and does not detect AI-written prose. Switch if you teach programming and want to compare student code submissions against each other yourself. Stay with Copyleaks if you need AI text detection and prose plagiarism matching, which Dolos does not do.
- **JPlag** (Open source, Free (self-hosted)): Finds pairwise similarities among a set of programs and shows them in a report viewer; it compares source code in many languages and does not read essays or detect AI-written prose. Switch if you grade programming assignments and want a local Java tool that compares submissions pairwise. Stay with Copyleaks if you check essays or articles, since JPlag compares source code only.

## Open-source options in detail

- **SlopTotal** (https://github.com/pablocaeg/sloptotal): Licence: MIT; Commercial use: Yes (MIT).; Runs on: Runs on CPU; loaded models need about 8.3 GB of RAM; GPU optional.; Setup: moderate: One docker run command; models download on first start.; Last commit: 2026-11-03; Last release: 2026-11-03; GitHub stars: 114 (2026-11-13)
- **Binoculars** (https://github.com/ahans30/Binoculars): Licence: BSD-3-Clause; Commercial use: Yes for the code (BSD-3-Clause); check the licence of the Falcon models you download.; Runs on: Python 3.9; two 7B models, so a GPU or large-memory machine.; Setup: hard: Clone the repo, pip install, then download two 7B models.; Last commit: 2024-05-14; GitHub stars: 435 (2026-11-13)
- **Fast-DetectGPT** (https://github.com/baoguangsheng/fast-detect-gpt): Licence: MIT; Commercial use: Yes (MIT).; Runs on: Authors ran it on an 80 GB A100; the local demo defaults to gpt-neo-2.7B.; Setup: hard: Python 3.8 and PyTorch 1.10 environment plus model downloads.; Last commit: 2026-02-07; GitHub stars: 440 (2026-11-13)
- **Open Detector** (https://github.com/Imalwayshere/Open-Detector): Licence: MIT; Commercial use: Yes (MIT); the Hugging Face model card also states MIT.; Runs on: Python with PyTorch and Transformers; BERT-base model, 512-token input.; Setup: moderate: pip install transformers torch, then a short Python script.; Last commit: 2026-11-12; GitHub stars: 254 (2026-11-13)
- **SynthID Text** (https://github.com/google-deepmind/synthid-text): Licence: Apache-2.0; Commercial use: Yes (Apache-2.0), but the repo calls itself a reference implementation, not for production.; Runs on: Any GPU such as a T4 for Gemma 3 270M; GPT-2 runs on CPU.; Setup: moderate: Python virtual environment and a Jupyter notebook from the repo.; Last commit: 2026-10-26; GitHub stars: 1,300 (2026-11-13)
- **Dolos** (https://github.com/dodona-edu/dolos): Licence: MIT; Commercial use: Yes (MIT).; Runs on: Node.js 22 or newer, or Docker; a free hosted web app also exists.; Setup: easy: npm install -g @dodona/dolos gives a CLI; web hosting needs Docker.; Last commit: 2026-11-12; Last release: 2026-10-19; GitHub stars: 357 (2026-11-13)
- **JPlag** (https://github.com/jplag/JPlag): Licence: GPL-3.0; Commercial use: Yes; GPL-3.0 means sharing source if you distribute changes.; Runs on: Java SE 25; runs locally, and no code or results are uploaded.; Setup: moderate: Download a release jar and run it on Java 25.; Last commit: 2026-10-05; Last release: 2025-12-11; GitHub stars: 2,000 (2026-11-13)

## Questions

### What is the best alternative to Copyleaks in 2027?
Originality.ai is the best overall Copyleaks alternative on this page ($12.95/mo billed yearly). For no cost, GPTZero has a free plan (10,000 words a month, 1 advanced scan). To self-host, SlopTotal is open source (MIT).

### Is there a free version of Copyleaks?
Yes. Copyleaks has a free plan: 25,000 characters per free scan; no free plan on pricing page. Paid plans start at $13.99/mo billed yearly, checked on 12 Nov 2026.

### Is there a 100% free alternative to Copyleaks?
Yes. SlopTotal, Binoculars, Fast-DetectGPT, Open Detector, SynthID Text, Dolos, JPlag are open source and free to self-host. GPTZero, Originality.ai, Winston AI, ZeroGPT, Quetext, Scribbr have a free plan with limits, shown in the table.

### What is cheaper than Copyleaks?
Isgen starts at $8/mo billed yearly, against $13.99/mo billed yearly for Copyleaks, as listed on each vendor's pricing page on 12 Nov 2026.

### How much do Copyleaks alternatives cost for a team of 5?
If each of 5 people buys the entry paid plan, at the prices Zekai checked on 13 Nov 2026, the monthly cost is Isgen $40/mo, ZeroGPT $44.95/mo, Winston AI $50/mo, against Copyleaks $69.95/mo for Copyleaks. Team and business plans can cost more per seat. The Zekai Cost Finder on this page recalculates for any team size.

### Which is better, Originality.ai or Copyleaks?
Pro gives 200K words (2K credits) a month with 30-day scan history, bulk scan, shareable reports and a Chrome extension; Copyleaks Personal gives 100 credits of 250 words each, about 25,000 words. Choose Originality.ai if you audit freelance copy for a publisher and want 200K words a month with team seats and scan history. Stay with Copyleaks if you need plagiarism checks across 30 languages plus image detection from one credit pool.

### Why are people leaving Copyleaks?
The documented reasons are: Personal costs $16.99 a month billed monthly versus $13.99 a month billed annually, and Pro $99.99 monthly versus $74.99 annually; the pricing page lists no free plan (12 Nov 2026); Personal includes 100 credits a month, with one credit covering up to 250 words or 1 image, which is roughly 25,000 words; Pro includes 1,000 credits and 25 seats, and the API is sold through sales for education and enterprise (12 Nov 2026). Each is sourced in the section above.

### What is better than Copyleaks?
It depends on the job: GPTZero for sentence highlights and a monthly free quota, Turnitin for institutions, Originality.ai for bulk publisher checks, Winston AI for images.

## Related on Zekai

- [GPTZero alternatives](https://zekaiwork.com/alternatives/gptzero/)
- [Winston AI alternatives](https://zekaiwork.com/alternatives/winston-ai/)
- [ZeroGPT alternatives](https://zekaiwork.com/alternatives/zerogpt/)
- [Turnitin alternatives](https://zekaiwork.com/alternatives/turnitin/)
- [AI for Education & E-learning](https://zekaiwork.com/professions/ai-education-elearning-teaching-tools/)

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Live table, team cost finder and price alerts: https://zekaiwork.com/alternatives/copyleaks/