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Empirical Formula Calculator

Empirical Formula Calculator


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An online empirical formula calculator allows you to find empirical formula corresponding to the given chemical composition. This combustion analysis calculator considers the symbol & percentage mass of the element & determine the simplest whole-number ratio of atoms in a compound.

Just read on the context to understand how to find the empirical formula, its basic definition in chemistry, 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!

What is the Empirical Formula?

According to chemistry definition, the empirical formula of a chemical compound is referred to as the simplest positive integer ratio of atoms present in a compound. A simple, but actual example of this concept is that the empirical formula of sulfur monoxide would simply \(SO\) as it is derived from formula disulfur dioxide, \(S_{2}O_2\). You can try an online empirical formula calculator to find the relative ratios of different atoms in a compound.

Remember that the molecular shows the number of each type of atom in a molecule. The structural formula is the thing that shows the arrangement of the molecule.

Empirical Formula Examples:

The molecular formula for glucose is \(C_{6}H_{12}O_6\). It has \(2\) moles of hydrogen \((H)\) for every mole of carbon \((C)\) and oxygen \((O)\). The empirical formula for glucose is \(CH_{2}O\).

Ribose has a molecular formula of \(C_{5}H_{10}O_5\) that can be reduced to the empirical formula \(CH_{2}O\).

Key Points:

  • Empirical formulas are referred to as the simplest form of notation
  • When it comes to molecular formula for a compound, it is equal to, or a whole-number multiple of, it’s empirical formula
  • Empirical formulas are not unique just like molecular formulas, even can describe a number of different chemical structures or isomers
  • If you need to determine an empirical formula, then the composition mass of its elements can be considered to mathematically determine its ratio

Formula to Calculate Number of Moles:

Use the given formula to calculate the number of moles of element:

\(\text { Number of moles} = \frac {\text { Mass given in grams}}{\text { Molar mass of element}}\)

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

Also, the online empirical formula calculator also uses the above formula to find the number of moles for a given composition of elements in a compound.

How to Find Empirical Formula Step-by-Step:

Basically, it is the reverse process that used to calculate a 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.
  • \(\text { Number of moles} = \frac {\text { Mass given in grams}}{\text { Molar mass of element}}\)
  • Number of moles of carbon = \(\frac{40}{12}\)
  • Number of moles of carbon = \(3.33 \text { moles}\)


  • Number of moles of hydrogen = \(\frac {6.72}{1.01}\)
  • Number of moles of hydrogen = \(6.65 \text { moles}\)


  • Number of moles of oxygen = \(\frac {53.28}{16}\)
  • Number of moles of oxygen = \(3.33 \text { moles}\)


\(100 \text {grams}\) 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 \(CH_{2}O\).

Also, our online empirical formula calculator considers these equations for finding the simplest positive integer ratio of atoms present in a compound (chemistry).

How to Calculate Empirical Formula With Calculator?

The empirical formula calculator is the best way to find an empirical formula from percent composition. Just you have to follow the given points for the exact calculations:


  • First, enter the symbol of the elements for which you want to determine the formula
  • Now, you need to enter the percentage of mass into the designated fields
  • Then, hit the calculate button


The empirical formula solver calculates:

  • The empirical formula of the compound
  • Step-by-step calculations for empirical formula

Empirical Formula Practice Problems:

Let’s take a look:

Problem 1:

A compound containing \(60.0\%\) sulfur and \(40.0\%\) oxygen by mass, what it’s empirical formula?

Answer: \(SO_3\)

Problem 2:

A compound consists of a compound containing \(38.8%\) carbon, \(16.2%\) hydrogen, and \(45.1%\) nitrogen, what its simplest ratio formula?

Answer: \(CH_{5}N\)

Problem 3:

A borane is a compound that consists of both hydrogen and boron – if a borane consists of only \(88.45%\) boron, then what’s the simplest ratio formula for a compound?

Answer: \(B_{5}H_7\)

Frequently Ask Questions (FAQ’s):

What do empirical formulas look like?

It is the chemical formula of compounds that 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 \((C_{2}H_4)_n\).


Remember that the empirical formula is referred to as the smallest whole-number ratio. That’s the reason why it’s is also said to be the simplest ratio. The technique for determining the simplest ratio formula can be considered in almost any real-world solution. When it comes to real-world chemistry, it becomes even trickier since atoms sometimes participate in unusual bonds, thus, these formulas aren’t necessarily accurate. Having an idea of what reaction is going to produce ensures that the reactions safer and more efficient to the consumer of the reaction. So, keep the empirical formula calculator to find the simplest whole-number ratio as well as the empirical formula of the compound with a step-by-step solution.


From the source of Wikipedia : Basic definition & example.

From the site of Study.com : Manual calculation of the simplest ratio formula.

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