Molarity calculator the grams you need, and what they cost
Pick a chemical, the strength and how much you need. We work out the grams, then the cheapest way to buy them from 14 stores we compare.
- You need
- 58.4 grams
- of Sodium Chloride, molar mass 58.44 g/mol
- That much costs
- $0.45
- $0.45 per litre of solution, at the lowest price per gram we found
Weigh it out, dissolve it in less water than you need, then top up to the full amount.
Lab stock solutions, worked out
At the lowest price per gram we found. Open one to see every price, with the calculator set to that recipe.
- 5 M sodium chloride$2.27292 grams in 1 litre
- 1 M Tris$11.36121 grams in 1 litre
- 1 M Tris hydrochloride$24.43158 grams in 1 litre
- 0.5 M EDTA, disodium salt (anhydrous)$6.95168 grams in 1 litre
- 10 M sodium hydroxide$0.69400 grams in 1 litre
- 1 M potassium chloride$1.2374.5 grams in 1 litre
- 1 M magnesium chloride hexahydrate$4.52203 grams in 1 litre
- 1 M magnesium sulfate (anhydrous)$0.89120 grams in 1 litre
- 1 M calcium chloride dihydrate$3.73147 grams in 1 litre
- 3 M sodium acetate trihydrate$11.10408 grams in 1 litre
- 1 M potassium phosphate, monobasic$3.19136 grams in 1 litre
- 0.5 M sodium phosphate, dibasic (anhydrous)$1.9171 grams in 1 litre
- 1 M glucose$4.54180 grams in 1 litre
- 1 M glycine$7.9575.1 grams in 1 litre
- 1 M citric acid$1.04192 grams in 1 litre
- 1 M HEPES$116.8223.8 grams in 100 millilitres
How to make a molar solution
- Work out the grams. Grams = molarity × litres × molar mass. The calculator above does it for you.
- Weigh it out. On a balance, into a clean beaker.
- Dissolve it in less water than you need. About three quarters of the final amount, stirring until it is clear.
- Top up to the full amount. In a volumetric flask or measuring cylinder, then mix again.
What the words mean
- Molarity (M)
- Moles of the chemical in each litre of solution. 1 M sodium chloride is 58.44 grams made up to 1 litre
- Millimolar (mM)
- A thousandth of that: 100 mM is 0.1 M
- Molar mass
- The weight of one mole, in grams. A hydrate weighs more than the dry chemical, so use the molar mass on your bottle's label
- The formula
- grams = molarity × litres × molar mass
More free tools
How it works: grams = molarity × litres × molar mass, with the molar mass from PubChem unless you type your own. "Cheapest way to buy it" uses whole packs from one store. Prices cover 3,967 chemicals: each store's in-stock pack price, in US dollars at European Central Bank rates of 2026-10-29, without shipping or tax.