Grams per Mole to Daltons Converter

g/mol

Common Conversions

g/mol	Da
1	1
18.015	18.015
58.44	58.44
100	100
180.16	180.16
342.3	342.3
1000	1000
10000	10000
50000	50000
100000	100000
500000	500000
1000000	1000000

Why this conversion matters in chemistry

Drug-product molecular weights appear in g/mol on regulatory filings (acetylsalicylic acid 180.16, acetaminophen 151.16, atorvastatin 558.64), and in Da on the corresponding mass-spectrometric identity confirmation. The two notations are numerically equivalent because the gram is defined as Avogadro's number of u. The only refinement that sometimes matters is monoisotopic versus average mass — ASA's average mass is 180.16, but its monoisotopic mass (using ¹²C, ¹H, ¹⁶O exclusively) is 180.0423, which is what an HRMS spectrum actually measures.

Formula

Da = g/mol × 1

Worked Examples

18.015 g/mol = 18.015 Da

Water — the textbook reference, where the molar mass and the per-molecule mass match exactly.

180.16 g/mol = 180.16 Da

Glucose, average mass — the same number on a stoichiometry sheet and a mass-spec result panel.

66500 g/mol = 66500 Da

Bovine serum albumin — the protein-chemistry reference, equivalently 66.5 kDa.

342.30 g/mol = 342.30 Da

Sucrose — the disaccharide whose molar mass anchors carbohydrate-chemistry calculations.

Frequently Asked Questions

How do I convert g/mol to Da?

No arithmetic conversion is needed — the numerical value is identical. 18.015 g/mol equals 18.015 Da, by the construction of the mole and the dalton.

Are u, Da, and amu the same unit?

Yes. The dalton (Da), the unified atomic mass unit (u), and the older amu are the same — defined as 1/12 the mass of an unbound ¹²C atom in its electronic ground state.

When does the conversion come up?

At the boundary between synthetic chemistry (which writes molar masses in g/mol) and analytical or structural biology (which writes per-molecule masses in Da). The conversion is the identity, but the notation distinction marks the audience.