Three-to-One Amino Acid Converter

Convert three-letter amino acid codes to single-letter format. Upload a file or paste your amino acid sequences below.

Input (Three-letter amino acid codes)

Text/FASTA

Click to upload or drag and drop

FASTA or text file

Max size: 50MB

Conversion options

Output formatting

Use uppercase output (A vs a)Preserve FASTA headers

Amino acid handling

Include unknown amino acids as XConvert modified amino acids

Output (One-letter amino acid codes)

FASTA