Free · No account · On-device matching
Text similarity checker
Compare your writing with sources.
See shared phrases across a draft and up to five sources you supply. Inspect the evidence and check citations—not a plagiarism verdict or an internet scan.
- Your draft
- Each weekday, the reading room opens before sunrise.
- Supplied source
- For early visitors, the reading room opens before sunrise.
A place to review, not a verdict.
Start with the text, not a guess.
Compare with sources you supply. We do not scan the web or assign an originality score.
Your document
The writing you want to review
Reference sources
Paste known sources, not website addresses
Your evidence will appear here.
See matching passages, their sources and the words included in the calculation. No black-box verdict.
A considered review in three steps
Add your material
Paste a primary draft and label one to five sources. Only material you supply is compared.
Set the scope
Choose a minimum phrase length and optional exclusions, or use Repeat mode for a single draft.
Read, then record
Inspect shared wording in context, check attribution and save a report with the details you choose.
What the percentage measures
Matching finds consecutive Unicode letter-and-number word runs of at least 4, 6 (default), 8 or 12 words. Spaces and punctuation are ignored; internal curly apostrophes are normalized. Unicode NFKC normalization harmonizes compatible character forms. Case folding is optional; accents are retained.
Main coverage counts the union of matched, eligible draft-word positions across sources. Each word counts once. Reverse coverage uses each source's eligible words as its denominator, so swapping draft and source can change the percentage. Source percentages are not additive.
Evidence shows the first 150 maximal passages per source, with one actual source occurrence per displayed passage. Coverage includes every qualifying matched position, even when the evidence list is capped. With no eligible words, coverage is unavailable—not zero.
Know what you exclude
Optional quotation exclusions recognize balanced straight double quotes, curly double quotes, guillemets and curly single quotes. Reference exclusion starts at the final standalone References, Bibliography or Works Cited heading and runs to the end; a later Markdown heading prevents that exclusion.
Both draft and sources are affected. Matches cannot bridge excluded gaps. Inspect gray highlights for mistakes: recognizing quotation marks or a heading does not validate a citation.
Know the boundaries
No web or academic corpus is searched. There is no AI or semantic matching: paraphrases, translated ideas and unsupplied sources can be missed. Unspaced Chinese, Japanese or Korean text may be under-segmented, making word counts and matches less useful.
Each text allows 10,000 words and 60,000 UTF-16 characters. UTF-8 .txt or .md imports have a 256 KB limit; PDF, DOCX, URLs and OCR are unsupported. The cancellable local worker stops checks after 15 seconds; speed depends on your device.
Review evidence, not a verdict
Writers can check quotations, editors can trace shared wording, and students can review assigned readings. Read surrounding sentences and verify attribution. Review labels record your judgment, not verification by the tool.
Repeat mode groups exact whole normalized sentences using punctuation, line breaks and Intl sentence segmentation when available. It displays up to 150 groups and 100 occurrences per group, with complete totals. Repeated occurrences count copies beyond the first. Short or partly excluded sentences are omitted.
Local matching, deliberate sharing
The tool does not upload text or automatically persist drafts, sources or notes. Reload clears the workspace. Copy or save a TXT report with passages and notes, or keep it stats-only. If repeated evidence exceeds 120,000 characters, the report explicitly falls back to stats-only. Copied text and downloaded reports remain outside the workspace.
Manual search offers up to five position-sampled passages, not risk flags. Preview the exact query, then explicitly follow the Google link to search. Nothing is searched automatically. Sitewide ads and analytics still operate separately; read our Privacy Policy.
Similarity is not originality
Turnitin's similarity guidance distinguishes matches from proof of plagiarism. ByteVerse does not use Turnitin's database or scoring method and is not endorsed by Turnitin.
Purdue OWL's citation guidance explains that paraphrases and summaries still require attribution. Changing words does not remove the obligation to credit ideas.
Google's SEO Starter Guide says ordinary duplicate content is not a blanket spam-policy violation; abusive copying is different. This percentage predicts neither rankings nor penalties.
For editing, use Diff Checker for line-by-line changes, Word Counter for length, or Readability Checker for English reading estimates.
Frequently asked questions
- Does a similarity percentage prove plagiarism?
- No. It measures matching eligible words against only your supplied sources. Quotations and common wording can match legitimately. Zero coverage means no qualifying match under the current settings, not proof of originality. Review context and attribution, not just a percentage.
- Can I compare two texts or more than two?
- Yes: one primary draft with one to five labeled sources. Each text is limited to 10,000 words and 60,000 UTF-16 characters. UTF-8 .txt and .md imports are limited to 256 KB. PDF, DOCX and URL imports are not supported.
- How is this different from a duplicate sentence checker?
- Compare mode finds consecutive normalized word runs across supplied texts. Repeat mode groups exact whole normalized sentences within your draft, subject to the selected minimum word length. Neither mode detects AI writing, understands paraphrased ideas or produces an originality score.
- Do exclusions and review labels change the percentage?
- Quotation and reference-section exclusions remove eligible words on both sides, so they can change coverage. They do not validate citations. Source filters and the Not reviewed, Citation checked, Common wording and Needs revision labels organize evidence without changing the percentage.
- Is it free, and what happens to my text?
- Yes, with no account required and the stated limits. The tool does not upload text or save work automatically; reload clears the workspace. Manual searches send the previewed query to Google only if you follow the search link. Sitewide ads and analytics are separate.
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