How to Use the Solution Concentration Calculator
This calculator computes mass percent concentration (w/w%) โ the weight of solute as a percentage of the total solution weight. The formula is: concentration (%) = (solute mass / solution mass) ร 100, where solution = solute + solvent. Choose the mode that matches the two values you know and the calculator finds the third.
Mode 1 is for when you know the solute and solvent masses. For example, dissolving 20 g of salt in 80 g of water gives a 20 g / (20 + 80 g) = 20% solution. Mode 2 lets you work backward from a target concentration: enter solute mass and desired %, and it tells you how much total solution and solvent you need. Mode 3 works from a known solution mass and concentration to split it into solute and solvent amounts.
This calculator uses mass percent (w/w%). Other concentration units such as molarity (mol/L), molality (mol/kg), or volume percent (v/v%) require different formulas and are not calculated here. This tool is useful for chemistry labs, cooking recipes, cleaning product preparation, and pharmaceutical compounding.
Frequently Asked Questions
Mass % = (solute mass / solution mass) ร 100. It tells you what fraction of the total solution weight is the dissolved substance.
The solute is what dissolves (e.g., salt), the solvent is the dissolving medium (e.g., water), and the solution is the final mixture. Solution = solute + solvent.
0% means no solute (so the mass of solution makes no sense as a concentration problem) and 100% means pure solute with no solvent โ neither is a meaningful solution. Both extremes are excluded from calculation.