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Average Nucleotide Identity

§ ANI calculator

The ANI calculator estimates the average nucleotide identity using both best hits (one-way ANI) and reciprocal best hits (two-way ANI) between two genomic datasets, as calculated by Goris et al., 2007. Typically, the ANI values between genomes of the same species are above 95% (e.g., Escherichia coli). Values below 75% are not to be trusted, and AAI should be used instead. This tool supports both complete and draft genomes (multi-fasta).
For an introductory comment, see Rodriguez-R & Konstantinidis, 2014.
Examples: Escherichia coli, Escherichia, Escherichia vs Yersinia, Escherichia vs Xanthomonas.

§ Input data

Your name, a valid e-mail address, and a name to identify the job.


First genome in FastA format, or NCBI accession. For example, CM001142 for Escherichia fergusonii.


Second genome in FastA format, or NCBI accession. For example, AE005174 for Escherichia coli.

§ ANI options

How alignments are filtered.

How to fragment the genomes.