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Empirical Formula Calculator

Empirical Formula Calculator


Percentage of Mass:

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An online empirical formula calculator helps you to determine the empirical formula of your given chemical composition. Simply, this online calculator considers the symbol & percentage mass of the element and determines the simplest whole number ratio of atoms in a compound. Give a complete read to this content for better understanding about the useful information related to the empirical formula. But let’s start with definition, manual calculation and much more.

You can also try our online mole fraction calculator that helps you to calculate the mole fraction, moles of solute, moles of solvent according to the given input parameters.

Read on!

Empirical Formula Definition:

According to basic definition, it is the formula that shows the simplest ratio of elements, which found in the compound, not the actual numbers of atoms in the molecule. If the molecular formula cannot be reduced further, then empirical formula of the compound is the same as its molecular formula.

Also Known As: It is also known as the simplest formula because subscripts are the smallest whole number ratio between the elements.

For example: The glucose has molecular formula C6H12O6. It contains one mole of each carbon & oxygen and 2 moles of hydrogen. The simplest formula of glucose is CH2O.

Formula to Calculate Number of Moles:

The formula to calculate the number of moles of element is as follows:

Number of moles = Mass given in grams / Molar mass of element

Where, the molar mass of each element varies according to the presence of isotopes.

How to Find Empirical Formula Step-by-Step:

Basically, it is the reverse process used to calculate mass percentage. We have a complete step-by-step calculation.

Read on!


The molecule contains 40% carbon, 6.72% hydrogen and 53.28% oxygen. Determine the empirical formula of the compound?


Step 1:

In this step, we have to determine the moles of each element.

Number of moles = Mass given in grams / Molar mass of element

Number of moles of carbon = 40 / 12

Number of moles of carbon = 3.33moles


Number of moles of hydrogen = 6.72 / 1.01

Number of moles of hydrogen = 6.65moles


Number of moles of oxygen = 53.28 / 16

Number of moles of oxygen = 3.33moles


100 grams is taken as a sample just for easiness. Any sample can be used, then the ratio between elements remains the same.

Step 2:

Finding the ratio between the numbers of moles.

As the smallest ratio is 3.33, so divided it with each of three values

3.33 / 3.33: 6.65 / 3.33: 3.33 / 3.33

Step 3:

Find the simplest formula.

1 : 1.999 : 1

Step 4:

Finding empirical formula.

C : H : O

1 : 1.99 : 1

So, the simplest formula of the compound is CH2O.

Also, our online empirical formula calculator considers these equations for the accurate & speedy results in chemistry.

How to Use This Online Calculator:

To determine the simplest formula of any compound becomes very easy with this free online empirical formula calculator. Just you have to follow the given points for the exact calculations:

Swipe on!


  • Firstly, enter the symbol of the elements on which you want to do the calculations.
  • Very next, enter the percentage of mass in the designated field of the tool.
  • Lastly, hit the calculate button.


Once you fill in all the fields, the calculator shows:

  • Empirical formula of the compound.
  • Step-by-Step calculation.

Frequently Ask Questions (FAQ’s):

What do empirical formulas look like?

It is the chemical formula of compounds which shows the actual number of atoms or arrangements of atoms. This would be the proportion (ratio) of elements present in the compound.

What is a molecular formula vs empirical formula?

As the empirical formula shows the simplest ratio of atoms and molecular formulas display the actual number of atoms in a molecule, and structural formulas show how the atoms are bonded to each other.

What is the empirical formula of polyethylene?

The simplest formula of polyethylene is (C2H4)n.


As the empirical formula tells the ratio of the different atoms in the compound as well as the ratio holds true on the molar level. So, knowing the simplest ratio of atoms in a compound has great importance. Simply, account to this online empirical formula calculator that helps you to figure out the simplest whole number ratio as well as the empirical formula of the compound with complete manual calculation.


From the source of Wikipedia : Basic definition & example.

From the site of Study.com : Manual calculation of empirical formula.

From the authorized source of ACS : Empirical formulas of different compounds.