Molar Mass Calculator

Overview

The Molar Mass Calculator determines the mass of one mole of a chemical substance. It parses chemical formulas (e.g., H2O, C6H12O6) and calculates the total molar mass based on the atomic masses of the constituent elements. It also provides the elemental composition by mass percentage.

How to Use

Enter Formula: Type the chemical formula into the input field.
- Elements are case-sensitive (e.g., Co is Cobalt, CO is Carbon Monoxide).
- Use subscripts for numbers (e.g., H2O).
- Parentheses are supported (e.g., Ca(OH)2).
- Hydrates are supported (e.g., CuSO4·5H2O or CuSO4*5H2O).
Use the Periodic Table: You can also click on elements in the interactive periodic table to add them to your formula.
View Results: The calculator instantly updates to show the total molar mass and a breakdown of each element's contribution.

Formula & Math

Molar mass ( $M$ ) is calculated by summing the atomic masses ( $m_{a}$ ) of all atoms in the molecule:

M = \sum (N_{i} \times m_{a, i})

Where:

$N_{i}$ is the number of atoms of element $i$ .
$m_{a, i}$ is the atomic mass of element $i$ (from the periodic table).

Example: Water (H₂O)

Hydrogen (H): $1.008 g/mol \times 2 = 2.016 g/mol$
Oxygen (O): $15.999 g/mol \times 1 = 15.999 g/mol$
Total: $18.015 g/mol$

Elemental Composition

The calculator also shows the percentage composition by mass for each element:

% Mass = \frac{Total Mass of Element}{Total Molar Mass} \times 100%

FAQ

What is a mole?

A mole is a unit of measurement for amount of substance. One mole contains exactly $6.022 \times 1 0^{23}$ elementary entities (Avogadro's number).

Why is case sensitivity important?

Chemical symbols use case to distinguish elements. For example, Co represents the metal Cobalt, while CO represents a molecule of Carbon and Oxygen (Carbon Monoxide).

Can I calculate hydrates?

Yes! You can enter formulas like CuSO4*5H2O to calculate the mass of hydrated compounds.

Practical review checklist

Use the Molar Mass Calculator result as a planning number, then compare it with at least two nearby scenarios. A single calculation is useful, but the decision usually becomes clearer when you also test a conservative value and an optimistic value. Change one input at a time so you can see which assumption has the strongest effect. This is especially helpful when the inputs come from estimates, rounded measurements, future dates, or prices that may change before you act.

Before relying on the result, check that every unit matches the label in the form. Percent fields normally expect a percentage such as 5 rather than 0.05, date fields should use the actual calendar date, and money fields should be entered without currency symbols. If the result looks surprising, return to the inputs first. Most unexpected outputs come from a misplaced decimal, a mixed unit, or a value copied from another source with different rounding.

For important financial, health, building, laboratory, or engineering choices, treat the calculator as a transparent first pass. It helps you understand direction and scale, but it does not replace local rules, professional review, manufacturer tolerances, medical guidance, or your own measured data. Save the assumptions you used when comparing alternatives so later decisions are based on the same baseline.