How to use this calculator
- Choose a chemical formula or a known molar mass.
- Enter the sample mass and select its unit.
- Select Calculate and review the gram-to-mole substitution.
Formula and variables
n = m / M
| Symbol | Meaning | Unit |
|---|---|---|
| n | amount | mol |
| m | mass | g |
| M | molar mass | g/mol |
Worked example
36.03 g H2O corresponds to about 2.00 mol.
Interpretation
The amount in moles is the sample mass divided by the formula-specific molar mass.
Common mistakes
- Enter an explicit formula, not a compound name.
- Choose the unit used by the entered mass.
Frequently asked questions
How do I convert grams to moles?
Divide the sample mass in grams by the molar mass in grams per mole.
Can I enter a molar mass instead of a formula?
Yes. Select Enter molar mass and enter a positive value in g/mol.
Does capitalization matter in a chemical formula?
Yes. Element symbols are case-sensitive. CO is carbon monoxide. Co is cobalt.
Can I use scientific notation?
Yes. Enter values such as 6.022e23 or 1.0e-6 in a numeric field.
How should I round the result?
Keep extra digits during the calculation. Round the final result to the precision required by your data.