Protein weight calculator

Calculate the molecular weight of protein sequences with specified parameters.

Input (Protein sequences)

FASTA

Click to upload or drag and drop

FASTA file (.fasta, .fas, .fa, .txt)

Max size: 50MB

Calculation options

Mass type

Average mass

Uses average atomic masses (typical for biochemistry)

Monoisotopic mass

Uses exact mass of most abundant isotopes (for mass spectrometry)

Common modifications

Include peptide bond formation(subtract water for each peptide bond)

Each peptide bond releases one water molecule (18.015 Da). A protein with n amino acids has n-1 peptide bonds.

The calculator determines molecular weight by summing amino acid masses and accounting for:

Molecular weights (Da)

Numbers