Protein Molecular Weight Calculator

Estimate a protein's molecular weight from residue count.

Molecular weight (Da) 33,000

Molecular weight (kDa) 33

Formula: MW ≈ residues × 110 Da

Step-by-step with your numbers:

1. Values used:

2. Number of amino acids = 300

4. Molecular weight = 33,000Da

5. Molecular weight = 33kDa

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A quick estimate of a protein's mass from its length.

The math behind it

The average amino-acid residue weighs ~110 Da, so MW ≈ number of residues × 110.

300 residues → ~33,000 Da (33 kDa).

Exact mass?

Sum the actual residue masses from the sequence for precision.