Mole Fraction Calculator

Input mode

Moles Mass + Molar Mass

Precision

3 sig figs 6 sig figs

Introduction

Mole fraction expresses the share of each component in a mixture based on amount of substance. It is dimensionless, always between 0 and 1, and the fractions for all components sum to one. This makes mole fraction a natural choice for gas mixtures, liquid solutions, and ideal-mixture calculations where composition should be independent of units like grams or milliliters. You can enter data in two ways: type moles directly, or supply a mass together with the corresponding molar mass so the calculator converts each entry to moles. The values are then normalized to obtain x_i for every component.

The table highlights the dominant component with a badge and reports the running total Σx, helping catch typos and unit mix-ups. Very small fractions automatically display in scientific notation for readability, and you can switch between three or six significant figures when you need more detail. Naming components keeps exported summaries clear for notes and reports.

How to use

Pick Moles or Mass + Molar Mass.
Enter at least two components; add or remove rows as needed.
Provide names for clarity (e.g., A, B, solvent).
Choose precision and press Calculate to see n_i, x_i, Σx, and the dominant component.
Use Download TXT for a quick record or Download PDF for a formatted one-page summary.

Example

A 0.200 mol, B 0.300 mol, C 0.500 mol → total 1.000 mol; x_A=0.200, x_B=0.300, x_C=0.500 (dominant C).

Disclaimer. Educational use only. Not a substitute for professional judgment.