Created By : Rina Nayak

Reviewed By : Rajashekhar Valipishetty

Last Updated : Apr 25, 2023

Protein Molecular Weight Calculator is a free online tool that shows the protein's name and molecular weight. To receive the result in a fraction of a second, you must choose the amino acid name and press the calculate button.


What is the Purpose of Protein Weight?

Amino acids, carbon, hydrogen, sulphur, and carbohydrates are all found in protein. A protein is an example of a type of nutrition. These are huge, complicated molecules that play important roles in the human body. They will work on the structure of the body's cells, tissues, and organs.

The Western Blot technique involves putting a mixture of proteins on a specific gel and applying an electric field to separate them. The molecular weight of the proteins determines how much the components in the combination move. The lesser the molecular weight, the longer it will take to pass through the gel.

How can I use the Molecular Weight Calculator for Proteins?

The protein mass calculator is the simplest tool you'll ever use: simply select the desired amino acid combination from the ready-to-use list. The entire names of all the elements are listed, as well as their 3- and 1-letter codes.

The findings of our protein kDa calculator will be displayed in both universal atomic mass unit (u) and kilodaltons (kDa).

  • 1 u = 1 Da
  • 1 Da = 0.001 kDa

How can you determine a protein's molecular weight from its sequence?

It's very easy to determine the molecular weight of a protein. Simply sum all of the amino acid molecular weights in the sequence and remove the water molecular weight for each bond formed. Every peptide bond established between any two amino acids creates and expels a water particle, which is why the molecular weight of water is subtracted.

Molecular Weight = amino acid MW1 + amino acid MW2 +... + amino acid MWn - (18.0153 x (n - 1)), Where, n = total number of used amino acids.

The gram/mole is the weight of one mole of a substance, and Da is the basic unit of molecular weight. A note on units: kDa, u, and g/mol

Why not use g/mol instead of kilodaltons (kDa) and universal atomic mass units (u) in our protein size calculator?


Da and u are the basic units of molecular weight (molecular mass), and they are easy to use because they are the size of single atoms or particles. Kilodaltons are a thousand times larger than daltons.

The weight of one mole of a substance is expressed in g/mol, which is equal to 6.02214076 * 10^23 particles (the so-called Avogadro's number). The molar mass is measured in this unit.

FAQs on Protein Molecular Weight Calculator

1. In what units is molecular weight expressed?

The molecular weight of a substance is the mass of one mole. The standard units of measurement are grammes per mole.

2. Is kDa a measurement of molecular weight?

The atomic mass unit is known as the dalton (Da), and a kilodalton (kDa) is 1,000 daltons. As an example, a 64kDa peptide has a molecular weight of 64,000 kilos per mole.

3. Why is protein molecular weight important?

Protein molecular weight is an important parameter to validate because the primary structure is the most fundamental level of protein structure. Understanding the molecular weight of the unaltered protein can aid in the initial evaluation of the biomolecule's functionality. Metabolic regulation is one example.

4. How can I use the protein molecular weight calculator?

Click on the add another field button after selecting the first amino acid in the first field. To acquire the molecular weight and protein name in the output box, press the calculate button.