Molarity to mg/L Converter
Common Conversions
| mol/L | mg/L |
|---|---|
| 0.0001 M NaCl (58.44) | 5.844 mg/L |
| 0.001 M NaCl (58.44) | 58.44 mg/L |
| 0.01 M NaCl (58.44) | 584.4 mg/L |
| 0.1 M NaCl (58.44) | 5,844 mg/L |
| 1 M NaCl (58.44) | 58,440 mg/L |
| 0.001 M glucose (180.16) | 180.16 mg/L |
| 0.01 M glucose (180.16) | 1,802 mg/L |
| 0.1 M glucose (180.16) | 18,016 mg/L |
| 0.001 M CaCO₃ (100.09) | 100.09 mg/L |
| 0.01 M HCl (36.46) | 364.6 mg/L |
| 0.1 M HCl (36.46) | 3,646 mg/L |
| 0.05 M H₂SO₄ (98.08) | 4,904 mg/L |
Why this conversion matters in chemistry
Titrant standardization runs into this conversion routinely. A 0.1000 M KHP primary standard (MW 204.22 g/mol) is 20,423 mg/L on the equivalent mass-based prep — the form a USP <621> HPLC mobile-phase buffer worksheet expects. The conversion needs molecular weight as the bridge between moles and grams. The factor combines MW (g/mol) with the milli prefix (× 1000), netting MW × 1000 mg/L per mol/L. It comes up when titrant or stock-solution preparation crosses between molar and mass-based notations.
Formula
mg/L = mol/L × MW × 1000
Worked Examples
1 M NaCl (MW 58.44) = 58440 mg/L
1 M NaCl in mass-concentration terms — a high-end working stock.
0.001 M (MW 100) = 100 mg/L
1 mM of a MW 100 compound — a clean shortcut value.
0.1 M HCl (MW 36.46) = 3646 mg/L
0.1 M HCl in mg/L — the titrant strength on a mass basis.
0.01 M glucose (MW 180) = 1800 mg/L
10 mM glucose in mg/L — a typical assay-side working concentration.
Frequently Asked Questions
How do I convert molarity to mg/L?
Multiply by molecular weight (g/mol) and then by 1000. For NaCl (MW 58.44): 0.1 M × 58.44 × 1000 = 5844 mg/L.
Why does this need molecular weight?
Molarity counts moles per volume; mg/L counts mass per volume. Bridging the two notations needs the molar mass as the conversion between moles and grams. Without MW the conversion is undefined.
What's the shortcut form?
mg/L = mM × MW. Working in millimolarity rather than molarity drops the × 1000 factor cleanly. Useful when concentrations naturally land in the mM range.