Plagiarism Checker for Students
Hand in assignments with confidence. Check your essay, lab report, or thesis chapter for accidental duplicates — privately, for free, right before you submit.
Last updated: 2026-08-11 · Privacy
Why students need a plagiarism check
Accidental plagiarism — forgetting a citation, reusing a phrase from last semester, or quoting without quotation marks — is one of the most common reasons students lose marks. Most institutions use Turnitin; catching the same overlaps before submission is exactly what a student-side checker is for.
CopyCheck Online runs the core comparison locally in your browser. Nothing is uploaded, no account needed for free checks, and you can fix flagged passages with the built-in AI rewrite.
By the numbers
- 1Free checks: 20 local + 3 web searches per month (no login).
- 2Local check: 100% in-browser — your essay never leaves your device.
- 3Supports essays up to 10,000 characters (Chinese or English).
- 4AI rewrite (DeepSeek) turns flagged passages into your own words.
- 57-day history for logged-in users to track fixes.
Student checker vs Turnitin
| CopyCheck Online (you) | Turnitin (institution) | |
|---|---|---|
| When you use it | Before submitting | After submitting |
| Privacy | Text stays local | Stored in database |
| Free | Yes (free tier) | Paid by school |
| See matches yourself | Yes + source URLs | Only if enabled |
| Fix with AI rewrite | Yes | No |
Check before you submit
- 1Paste your essay
Copy-paste your draft or upload TXT/MD/PDF (up to 10,000 chars).
- 2Run Free Check
Instant local corpus match — no login, no upload.
- 3Fix flagged parts
Use AI Rewrite on overlapping passages, then re-check until clean.
Typical student scenario
My essay intro: "The Industrial Revolution transformed society by introducing mass production, urbanization, and new labor systems."
Similarity 34% · 1 match · "Industrial Revolution transformed society" → source: history-textbook.example.edu AI Rewrite: paraphrase suggested ✓
FAQ
Will this replace my university’s check?
No. Use it as a pre-submission safety net. Your school’s official checker is the final word.
Can teachers see my checks?
No. Local checks stay on your device; only logged-in history is on our servers, and only you can see it.
Is it really free?
Yes. 20 local + 3 web checks per month free, no credit card. Logging in raises the quota and unlocks history.
Sources
- · Free-tier policy: 20 local + 3 web checks/mo (server-enforced)
- · Local engine: shingle fingerprinting, browser-side (lib/engine.ts)