About the Solution Preparation Calculator
How much solid to weigh out, or stock to pipette, to make a solution of a given strength and volume.
Also known as: how to make a solution, prepare molar solution, weigh out solute, lab solution calculator.
How to use this calculator
- Enter solute formula, target concentration, volume to prepare, reagent purity and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Open “Step-by-step” to see how the answer was worked out.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
mass = molarity × volume (L) × molar mass ÷ purity
Worked example
Using the values pre-filled in the calculator above:
- Solute formula: NaOH
- Target concentration = 0.1 mol/L
- Volume to prepare = 500 mL
- Reagent purity = 99 %
- Stock concentration (0 for solid) = 0 mol/L
the calculator returns:
- Solid to weigh out: 2.0201 g
- In milligrams: 2,020.1
- Moles of solute: 0.05 mol
- Molar mass: 39.997 g/mol
Working
n = 0.1 mol/L × 0.5 L = 0.05 molm = 0.05 × 39.997 = 1.9999 gAdjusted for 99% purity → 2.0201 g