Grams per Mole to AMU Converter

g/mol

amu

Common Conversions

g/mol	amu
1	1
2	2
12	12
16	16
18.015	18.015
28	28
44	44
58.44	58.44
98.08	98.08
180.16	180.16
342.3	342.3

Why this conversion matters in chemistry

Molar mass in g/mol describes a mole of particles; atomic mass in u (amu) describes a single particle. The numerical values are identical by construction — water at 18.015 g/mol is also 18.015 u per molecule, and the same identity holds for every other compound. The equivalence falls out of the mole definition itself: Avogadro's number was chosen so that 12 g of carbon-12 atoms is exactly Nₐ atoms × 12 u each. The conversion is the identity, useful at the junction between molar-scale stoichiometry and single-molecule mass-spectrometric measurements.

Formula

amu = g/mol × 1 (numerically identical)

Worked Examples

18.015 g/mol = 18.015 amu

Water — the textbook example, where the molar mass and the per-molecule mass write as the same number.

12 g/mol = 12 amu

Carbon-12 by definition — the calibration anchor that pins the entire u-scale.

58.44 g/mol = 58.44 amu

Sodium chloride formula mass — useful in any calculation bridging salt stoichiometry and per-ion mass spectrometry.

180.16 g/mol = 180.16 amu

Glucose — the standard molar-mass reference for any monosaccharide-related calculation.

Frequently Asked Questions

Are g/mol and amu the same number?

Yes — the molar mass in g/mol equals the molecular or atomic mass in amu, exactly. The equivalence is built into the mole concept and rests on Avogadro's number.

Why are they numerically equal?

Because Avogadro's number is defined so that one mole of carbon-12 atoms — 12 grams of mass — corresponds to 12 amu per atom × Nₐ atoms. Once that's pinned, every other molar mass and atomic mass equality follows.

What's the physical meaning?

g/mol is a per-mole quantity (macroscopic), amu is a per-particle quantity (atomic scale). The numerical equivalence is what links the two scales without requiring any extra arithmetic.

Is dalton the same as amu?

Yes. 1 Da = 1 amu = 1 u. All three names refer to the unified atomic mass unit, defined as 1/12 the mass of a neutral carbon-12 atom in its electronic ground state.