Peptide Calculator
Please enter a valid sequence (only letters A-Z, no spaces).
pH must be between 0 and 14.
Results
Molecular Weight (Da)
Net Charge at pH
Extinction Coefficient (M⁻¹cm⁻¹)
Formula: Molecular weight = sum of residue weights + water weight (18.02). Net charge = sum of charged residues contributions at given pH using Henderson-Hasselbalch. Extinction coefficient = 5500*Trp + 1490*Tyr + 125*Cys (cystine).