Find out what your sequence is related to.
Paste a stretch of DNA, RNA or protein and compare it against public sequence records to see what else looks like it — the same idea behind NCBI's BLAST, restyled so the tool gets out of the way of the result.
Four ways to compare a sequence
Each combination compares a different kind of query against a different kind of database — pick the one that matches what you're holding.
Nucleotide BLAST
Compare a DNA or RNA sequence against nucleotide records.
blastn →Protein BLAST
Compare a protein sequence against protein records.
blastp →Translated search
Compare a translated DNA sequence against protein records.
blastx →Protein vs. genome
Compare a protein sequence against translated nucleotide records.
tblastn →What BLAST actually does
BLAST — the Basic Local Alignment Search Tool — is run by NCBI, the National Center for Biotechnology Information, part of the U.S. National Library of Medicine at the NIH. It's one of the most-used tools in biology: researchers paste in a sequence they've read off an instrument and ask "has anyone seen this before, and if so, in what?"
Rather than needing an exact match, BLAST looks for regions of similarity — close enough to suggest a shared gene, a shared ancestor, or a shared function — and ranks what it finds by how confident it is in the match. That ranked list is what turns a raw string of letters into something a scientist can actually act on.
NCBI's own version of this tool has done that job reliably for three decades, but its interface hasn't kept pace with the rest of the web — dense tables, tiny type, and a landing page that's really a directory of eight near-identical tools. This redesign keeps the exact same workflow and restates the same facts, just laid out the way a 2026 tool would be.
- Based in
- Bethesda, Maryland, USA — on the NIH campus
- The real tool
- blast.ncbi.nlm.nih.gov
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Paste a sequence
DNA, RNA or protein — plain letters, no formatting required.
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Pick a search type
Match the kind of query you have to the kind of database to search.
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Read the ranked hits
Sorted by how confident the match is, with the alignment underneath each one.