How do you convert moles to grams?

Multiply moles by molar mass: mass (g) = moles (mol) × molar mass (g/mol). For example, 2 mol of water (18.015 g/mol) = 36.03 g.

What is molar mass and where do I find it?

Molar mass is the mass of one mole of a substance in g/mol. Pick from the preset list, or add the atomic masses of each element (× count) from the periodic table.

How does this relate to stoichiometry?

Stoichiometry uses mole ratios from a balanced equation. After finding moles of product, convert to grams by multiplying by the product's molar mass.

How do I convert grams back to moles?

Rearrange the formula: moles = grams ÷ molar mass. Divide the mass you have by the molar mass of the substance.

Does Avogadro's number come into this?

Not directly for moles to grams — that uses molar mass only. Avogadro's number (6.022 × 10²³) converts moles to particle count.

Can I enter decimal values?

Yes. Both the moles and molar mass fields accept decimals, so you can enter 0.5 mol or 18.015 g/mol.

Moles to Grams Calculator

Convert moles to grams using mass = moles × molar mass. Pick a compound preset or type the molar mass directly.

Enter Values

Amount (mol)

Common Compound (optional)

Molar Mass (g/mol)

Enter moles and molar mass on the left to calculate mass in grams.

Common Molar Masses

Compound	Formula	g/mol
Water	H2O	18.015
Carbon Dioxide	CO2	44.009
Sodium Chloride	NaCl	58.44
Glucose	C6H12O6	180.159
Sulfuric Acid	H2SO4	98.079
Sodium Hydroxide	NaOH	40.00
Acetic Acid	CH3COOH	60.052
Sucrose	C12H22O11	342.297

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Summary

The Moles to Grams Calculator converts an amount of substance (in moles) to mass (in grams) using mass = moles × molar mass (g/mol). Enter the number of moles, then pick a compound from the preset list or type a molar mass directly. The result updates instantly in your browser.

How it works

Enter the amount in moles (e.g. 2.5 mol).
Pick a compound from the preset list to auto-fill its molar mass, or type the molar mass in g/mol manually.
The tool multiplies moles by molar mass and shows mass in grams, with a copy button for the result.

Use cases

Converting moles of a reagent to grams for lab preparations.
Checking stoichiometric calculations in chemistry homework.
Looking up the molar mass of common compounds like water, glucose, or NaCl.
Teaching the mole concept and the molar mass relationship.
Preparing solutions when a recipe specifies amounts in moles.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu