g/L to Molarity Converter

g/L

Common Conversions

g/L	M
0.584	0.01
5.844	0.1
9	0.154
29.22	0.5
58.44	1
116.88	2
175.32	3
292.2	5
350.64	6
584.4	10
701.28	12

Why this conversion matters in chemistry

A balance gives you grams; a titration wants moles. The conversion that connects the two is M = (g/L) / MW, and it's the calculation behind every reagent prep that starts with weighing solute into a volumetric flask. NaCl at 58.44 g/L is exactly 1 M because the molar mass of NaCl is 58.44 g/mol — the convenient coincidence that makes sodium chloride the textbook reference for molarity. Normal saline is 9 g/L of NaCl, which works out to 0.154 M, or 154 mM — the number a clinical-chemistry text writes as 154 mEq/L of Na⁺ since NaCl is a 1:1 electrolyte.

Formula

M = g/L / MW (molar mass in g/mol)

Worked Examples

58.44 g/L NaCl = 1 M

The textbook anchor — sodium chloride at its molar mass per liter is exactly one molar.

9 g/L NaCl = 0.154 M

Normal saline — 0.9% w/v NaCl, the standard isotonic solution for IV fluids and biochemistry buffers.

40 g/L NaOH = 1 M

One molar sodium hydroxide — convenient because NaOH's molar mass is 39.997 g/mol, close enough to round to 40 in practice.

180.16 g/L glucose = 1 M

One molar glucose — a useful reference for any sugar chemistry where mass-based recipes need to land in molarity.

Frequently Asked Questions

How do I convert g/L to molarity?

Divide by the molar mass in g/mol. So 9 g/L of NaCl divided by 58.44 g/mol gives 0.154 M — the molarity of normal saline.

What about mg/mL?

mg/mL equals g/L by simple unit cancellation, so the same formula applies: M = (mg/mL) / MW. A 5 mg/mL stock of a 250 g/mol compound is 5/250 = 0.020 M, or 20 mM.

How do I get moles from g/L?

Multiply concentration by volume to get moles. So (g/L × V_L) / MW gives moles directly, which is the same as M × V.

What's normal saline in molarity?

Normal saline is 0.9% w/v NaCl, which is 9 g/L. Dividing by NaCl's 58.44 g/mol molar mass gives 0.154 M, equivalently 154 mM. That's the value on every clinical-chemistry table for sodium concentration in plasma.