Moles to Grams Calculator
Convert moles to grams or grams to moles. Type a molar mass in g/mol, or enter a formula such as H2O so the page sums atomic weights first. Formula: n = m / M.
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How to convert moles and grams
- Enter moles or grams, not both. Leave the side you want solved blank.
- Type molar mass in g/mol, or keep a formula such as H2O so the page computes molar mass.
- Read moles, mass in grams, and the molar mass that was used.
- Confirm the formula parsing if you typed a compound. Nested groups such as Ca(OH)2 are supported.
Mole-mass conversion
n = m / M with molar mass M in g/mol
| Mole | SI amount of substance |
|---|---|
| Mass | Grams of sample |
| Molar mass M | Grams per mole of formula unit |
| Formula | n = m / M and m = n × M |
| Atomic weights | IUPAC typical values when a formula is parsed |
| Formula unit | Molecule or empirical unit counted by the formula |
What this page converts
Amount in moles and mass in grams are linked by molar mass. Two moles of water at about 18.015 g/mol weigh about 36.03 g. Enter moles to get grams, or grams to get moles.
Moles, grams, and molar mass
A mole counts formula units with Avogadro's constant. Grams measure mass on a balance. Molar mass is the bridge: grams per mole for that formula. You can type M directly or derive it from a formula on this page.
How the solve step works
Exactly one of moles or grams must be set. Molar mass comes from the number field or from parsing the formula. The page then applies n = m / M. Entering both moles and grams at once is rejected.
Limits
Hydrate dots such as CuSO4·5H2O are not parsed as one token. Expand them or use a typed molar mass. Informational only. See the disclaimer.