๐งซProtein Molecular Weight Calculator
Enter a single-letter amino acid sequence to calculate the protein's molecular weight.
Standard single-letter codes (A, R, N, D, C, Q, E, G, H, I, L, K, M, F, P, S, T, W, Y, V). Whitespace and numbers are ignored.
Free Protein Molecular Weight Calculator
This protein molecular weight calculator estimates a protein's molecular weight from its amino acid sequence using standard average residue masses. Each amino acid contributes its residue mass (the amino acid's mass minus a water molecule lost during peptide bond formation), and one water molecule (18.02 Da) is added back for the free N- and C-termini.
Paste a single-letter sequence โ the standard format used by UniProt and most sequence databases โ and get the total molecular weight in daltons and kilodaltons, along with the residue count and average residue mass.
Useful for molecular biology, biochemistry, and protein purification work. Free, runs entirely in your browser, no sign-up required.