Moles to Grams Calculator
Convert between moles and grams of a substance using its molar mass — either direction.
Moles from grams, or grams from moles, with the working shown.
How the moles to grams calculator works
Moles × molar mass = mass; mass ÷ molar mass = moles. That is the whole conversion — the molar mass is the bridge between the balance and the equation. Choose the direction, enter the amount and the molar mass (from the molar-mass calculator if you only have a formula).
Formula: mass = n × M · n = mass ÷ M
Worked examples
| Inputs | Result | Note |
|---|---|---|
| 10 g of water → moles | 0.55509 | 0.555 mol |
| 2 mol of NaCl → grams | 116.88 | 116.88 g |
| 25 g of CO₂ → moles | 0.56805 | 0.568 mol |
FAQFrequently asked questions
What is a mole?
An amount: 6.022 × 10²³ particles, chosen so that one mole of a substance weighs its formula mass in grams.
Why do I need the molar mass?
Because a balance measures mass but reactions happen in ratios of particles. Molar mass converts between the two.
How do I find the molar mass?
Add the atomic masses in the formula — the molar-mass calculator does it from the formula text.
Can I use kilograms?
Enter grams; a kilogram is 1,000 g. Millimoles are shown for small amounts.
Where these figures come from
- IUPAC — Standard atomic weights (2021 conventional values) — the molar-mass table
- NIST — CODATA 2018 fundamental physical constants — Avogadro constant, gas constant, speed of light
- NIST Chemistry WebBook — thermochemical data
- CSIRO — Australia's national science agency
Last checked: September 2026. Atomic masses are the IUPAC conventional values; constants are CODATA 2018; equations are the standard textbook forms.