Crossref Similarity Check pricing
2 plans read from crossref.org
Similarity Check per-document checkingFree Invoiced annually in January for the previous year’s usage.First 100 documents per year free · up to 25,000 words per document · subsequent rates are $0.75, $0.65, $0.55, $0.45, $0.30, or $0.25 per document by annual volume tier Read 9 Oct 2026 · crossref.org
Similarity Check annual service fee$40 a year Included in the annual membership fee invoice; prorated for the remainder of the calendar year when first joining.20% of annual Crossref membership fee · fee depends on membership tier Read 9 Oct 2026 · crossref.org
In short
- Crossref Similarity Check has a free plan (Similarity Check per-document checking).
- Paid plans published: 1, from $40 a year.
What the alternatives costAll alternatives →
| Tool | From | Free plan | Free trial |
|---|---|---|---|
| Copyleaks AI Detector | $13.99/mo | No | Yes |
| Copyscape | $4.95/mo | Yes | Yes |
| Noplag | $9.99/mo | Yes | Yes |
| Plagiarisma | $8.25/mo | Yes | Yes |
| Dolos | — | Yes | No |
| Originality.ai | $12.95/mo | Yes | Yes |
| PlagAware | €2.99/mo | Yes | Yes |
| DrillBit | — | No | No |