Concentration Calculator: % w/v, g/L, ppm and Molarity
Enter the mass of the substance and the final volume of the solution. See its strength as % w/v, g/L, mg/L and mol/L.
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Concentration
1.17% w/v
- Grams per litre
- 11.7 g/L
- mg/L (≈ ppm in water)
- 11,700 mg/L
- Molarity
- 0.2002 mol/L
- Millimolar
- 200.21 mM
mg/L ≈ ppm only for dilute solutions in water. Use the final solution volume, not the water added.
Show working
- % w/v = 5.85 g ÷ 500 ml × 100 = 1.17
- mol = 5.85 ÷ 58.44 = 0.1001
- M = 0.1001 ÷ 0.5 L = 0.20021 mol/L
How to use
- Enter the mass of solute in grams.
- Enter the final volume of the solution in ml.
- Pick the substance (or enter its molar mass) to see molarity.
Good to know
% w/v = grams of solute ÷ ml of solution × 100. g/L = grams ÷ litres. Molarity (mol/L) = (grams ÷ molar mass) ÷ litres. 5.85 g of salt (NaCl, 58.44 g/mol) made up to 500 ml gives 1.17% w/v, 11.7 g/L and 0.2 mol/L.
For dilute solutions in water, 1 mg/L is about 1 ppm, because a litre of water weighs about 1 kg. That is how TDS meters and water reports in India express dissolved salts. For strong solutions or other solvents, ppm by mass differs from mg/L.
Use the final volume of the solution, not the volume of water you added — dissolving a solid changes the volume slightly. Molar masses here are from standard atomic weights; copper sulphate is the common blue pentahydrate. This is for study and general use, not for preparing medicines.
Questions
How do I calculate % w/v?
Grams of solute ÷ ml of solution × 100. 10 g in 200 ml = 5% w/v.
How do I calculate molarity?
Moles = grams ÷ molar mass; molarity = moles ÷ litres of solution. 4 g NaOH in 1 L = 0.1 M.
Is mg/L the same as ppm?
For dilute water solutions, yes, approximately. 500 mg/L of dissolved salts ≈ 500 ppm TDS.
Where do I find molar mass?
Add up the atomic masses in the formula, or check the bottle label. NaCl = 23.0 + 35.45 = 58.44 g/mol.
Is anything stored?
No. All calculations run on your device.