Solution preparation calculator
Pick the formula, the target concentration and the final volume to see the mass to dissolve before filling up to the mark.
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How to use it
- Enter solute formula, target concentration, final volume and volume unit.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Mass (g) = molarity (mol/L) × volume (L) × molar mass (g/mol).
Example
Inputs: Solute formula = NaCl, Target concentration = 0.5 mol/L, Final volume = 250, Volume unit = milliliters (mL). Result: Mass to weigh: 7.305 g; Moles of solute: 0.125 mol; Molar mass: 58.4398 g/mol.
Limits and caveats
- Assumes 100% purity; for a less pure reagent divide the mass by the purity as a decimal.
- Use the hydrate formula if the solid you have is a hydrate.
Questions about this tool
How do I make 250 mL of 0.5 M NaCl?
Weigh about 7.305 g of sodium chloride, dissolve it in some water, then fill a volumetric flask to 250 mL.
Do I add 250 mL of water on top of the solid?
No. Fill up to a total of 250 mL, because the solute takes up part of the volume.
Why do CuSO4 and CuSO4·5H2O need different masses?
The hydrate carries water in its crystals, so its molar mass is higher and you weigh more for the same concentration.