Similarity Check per-document checking
Free
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
Checked 9 Oct 2026
Plans and prices
Crossref Similarity Check pricing
Similarity Check annual service fee
$40 a year
20% of annual Crossref membership fee · fee depends on membership tier
Checked 9 Oct 2026