Amino Acid Composition Calculator
Count the 20 standard amino acids in a peptide or protein and see the fraction of the sequence contributed by each residue. Sort the table by residue, count, or percentage, then copy it as CSV or TSV for use in a spreadsheet.
Results
Enter a valid sequence to see results.
How composition is calculated
For each residue, divide its count by the total sequence length and multiply by 100. The table includes zero counts. The total percentage uses unrounded values, while individual percentages display four decimal places.
Read the calculation method →Worked example
GASGAPGAG
Nine residues. G occurs four times (44.4444%), A three times (33.3333%), and P and S once each (11.1111% each).
Limitations
- Composition describes residue frequencies. Sequences with the same counts can have different residue orders and properties.