Protein Molecular Weight Calculator

Protein Molecular Weight Calculator: Calculate Protein Molecular Weight

Calculate the molecular weight of a protein sequence with this user-friendly Protein Molecular Weight Calculator. Input your protein sequence using standard one-letter amino acid codes (A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y), then click Calculate to get a detailed breakdown of the molecular weight in Daltons (Da). Perfect for molecular biology and biochemistry research!

How It Works

Enter your protein sequence using the keypad or keyboard, then click “Calculate” to see the molecular weight. The calculator displays the result, sequence length, and step-by-step calculations, scrolls to the result, and offers options to copy or share your results.

Protein Molecular Weight Calculator

Protein Sequence (One-Letter Codes)

Result

Molecular Weight:

Sequence Length:

Steps

About Protein Molecular Weight Calculator

The Protein Molecular Weight Calculator computes the molecular weight of a protein sequence in Daltons (Da) based on the amino acid sequence. It’s a simple tool for molecular biology and biochemistry research.

How to Use

  • Enter your protein sequence using standard one-letter amino acid codes (A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y; case-insensitive) in the text input or via the keypad buttons.
  • Click the “Calculate” button to compute the molecular weight. The page will scroll to the result.
  • The result, sequence length, and detailed step-by-step calculations will be displayed below.
  • Use the “Copy Result” button to copy the molecular weight, sequence length, and steps.
  • Share your result on Twitter, WhatsApp, or Facebook, or copy an embed code to include the calculator or result on your website using the share buttons.

Formulas

Protein Molecular Weight:

Molecular Weight = Σ(Amino Acid Weights) – (n-1) × 18.02 Da + 18.02 Da

Where:

  • Amino Acid Weights (Da): A=71.08, C=103.14, D=115.09, E=129.12, F=147.18, G=57.05, H=137.14, I=113.16, K=128.17, L=113.16, M=131.19, N=114.10, P=97.12, Q=128.13, R=156.19, S=87.08, T=101.11, V=99.13, W=186.21, Y=163.18
  • n = number of amino acids
  • 18.02 Da is subtracted per peptide bond (n-1 bonds)
  • 18.02 Da is added for N-terminal (H) and C-terminal (OH) groups

Important Notes

  • The sequence must contain only valid one-letter amino acid codes (A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y; case-insensitive). Invalid characters or empty sequences will trigger an error.
  • Calculations account for water loss in peptide bonds and include N-terminal and C-terminal groups.
  • Clipboard access requires a secure context (HTTPS). If copying fails, try accessing the calculator over HTTPS or copy manually.
  • The keypad is tailored for amino acid input with clear and navigation options.