Created By : Rina Nayak

Reviewed By : Rajashekhar Valipishetty

Last Updated : Apr 03, 2023

Molecular Weight Calculator Protein is a free online tool that displays the protein name and its molecular weight. You need to select the amino acid name and press the calculate button to get the gest in a fraction of seconds.


How to Calculate Protein Molecular Weight from Sequence?

Finding the Molecular Weight of Protein is so simple. Just add all the molecular weights of the amino acids in the sequence and subtract the water molecular weight for every bond created.

The reason to subtract the molecular weight of water is with every peptide bond formed between any two amino acids, a water particle is created and expelled.

Molecular Weight = minoacid MW1 + Aminoacid MW2 + . . . + Aminoacid MWn - (18.0153 x (n - 1))


n is the total number of used amino acids.

The basic unit of molecular weight is Da, u nad gram/mole is the weight of one mole of a substance.

Why Do We Need Protein Weight?

Protein is a material that includes amino acids, carbon, hydrogen, sulfur and carbohydrates. The type of nutrient is an example of a protein. These are large, complex molecules that are playing critical roles in the body. They will do work in cells, tissues, organs of the body's structure.

In the Western Blot technique, the combination of different proteins is placed onto a special gel and separated using the electric field. The substances in the mixture move by an amount determined by the protein molecular weight. The lower molecular weight means the greater distance it will travel through the gel.

If you would like to learn more about the other chemistry calculator that gives instant results, stay tuned to Chemistrycalc.Com

FAQ’s on Protein Molecular Weight Calculator

1. How to find the molecular weight of a protein?

The unknown protein molecular weight can be calculated using the equation for the linear plot i.e Log(Molecular Weight) = (-2.0742 x 0.7084) + 2.8 = 1.3305. 101.3305 = 21.4 kDa. The protein molecular weight from the sequence is molecular weight = Aminoacid MW1 + Aminoacid MW2 + . . + Aminoacid mWn - (18.0153 x (n - 1)). Use this formula to check the protein MW.

2. What is the molecular weight of proteins?

Proteins are made up of amino acid residues that are bound by peptide bonds between the amino nitrogen and carboxyl groups. The molecular weight of a protein can be predicted based on the known molecular weights of the amino acids if the sequence and composition of amino acids in a linear chain are known.

3. How to use the molecular weight calculator of protein?

Select the first amino acid in the first field and click on the add another field. Hit the calculate button to get the molecular weight, protein name in the output section.

4. What are the 4 types of proteins?

The four different types of proteins are primary, secondary, tertiary and quaternary.

5. What are the main jobs of protein?

The important jobs of protein are growth and maintenance of tissues in your body, biochemical reactions, maintain proper pH, balances fluids and others.

Protein Molecular Weight Calculator