# Mole Fraction Calculator

Calculate the mole fraction of a solution by entering the amount of solute and solvent below.

## Mole Fraction:

## On this page:

## How to Calculate the Mole Fraction of a Solution

The mole fraction is the ratio of one substance in a solution to the moles of all substances in a solution, and it’s commonly used in chemistry.^{[1]} So, in order to find the mole fraction of a substance in a solution, you will need to know the amount of the substance (solute) and the amount of the remaining substance (solvent).

Since a mole fraction is a ratio, you can find it by dividing the amount of one substance in a solution by the total amount of solution.

Need to calculate the amount of solution in moles? Try our mole calculator or grams to moles calculator.

### Mole Fraction Formula

So, to solve the mole fraction, you can use the following formula:

X_{A} = A (mol) / A (mol) + B (mol)

Thus, the mole fraction *X _{A}* of a substance

*A*in a solution of

*A*and

*B*is equal to the amount of solute

*A*in moles divided by the sum of the amount of solute

*A*in moles and the amount of solvent

*B*in moles.

A simpler representation of this formula might look like this:

mole fraction = solute (mol) / solute (mol) + solvent (mol)

**For example,** let’s calculate the mole fraction of solute *A* in a solution composed of 2 moles of solute *A* and 4 moles of solvent *B*.

X_{A} = 2 / 2 + 4 = 2 / 6 = 1 / 3

The mole fraction *X _{A}* in this example is equal to 1/3, or 0.33.

We can also find the mole fraction of *B* in this substance.

X_{B} = 4 / 2 + 4 = 4 / 6 = 2 / 3

The mole fraction *X _{B}* in this example is equal to 2/3, or 0.67.

It’s important to note that since the mole fraction is a ratio of one compound in a substance to the whole, the mole fractions of each compound in the substance should sum to **1**.

## References

- LibreTexts, Mole Fraction, 2021, July 2, https://chem.libretexts.org/@go/page/53833