Mass Percent Calculator
This mass percent calculator turns masses into a percentage: 10 g of salt in 90 g of water give a solution with 10 mass percent. It also works backwards, gives ppm and per mille, and includes a mixing cross for two solutions.
Example: What do you want to calculate: Percent from solute and solvent mass · Mass of the solute 10 g · Mass of the solvent 90 g → Result: Mass fraction w = 10 %. Source: Wikipedia – Massenanteil (DIN 1310, Gehaltsangaben). Updated: .
How it is calculated
Mass percent tells you how many grams of a substance are in 100 grams of solution: w = m(solute) / m(solution) · 100 %. The solution consists of the dissolved solute and the solvent, and its mass is the sum of both.
How it is calculated
Dissolve 10 g of salt in 90 g of water and the solution weighs 100 g, so the mass fraction is 10 %. Conversely, a 15 % solution with a total mass of 200 g needs 30 g of solute and 170 g of solvent. The calculator also gives the fraction in per mille (g per kg) and ppm (mg per kg), for example for trace substances.
Mixing cross
To make a third solution from two with different fractions, the mixing cross (alligation) helps: the differences between the target and the two starting values give the mass ratio. A 96 % and a 40 % solution make 70 % in the ratio 30 to 26 parts, so 53.6 g and 46.4 g for 100 g. Water counts as a 0 % solution, so you can dilute with it too.
- Do not confuse mass and volume: mass percent refers to mass.
- The sum of solute and solvent is the mass of the solution, not the solvent alone.
- For the mixing cross the target must lie between the two starting solutions.
Frequently asked questions
How do you calculate mass percent?
Divide the mass of the solute by the mass of the whole solution and multiply by 100. 10 g of salt in 90 g of water is 10 g out of 100 g, so 10 %.
What is the difference between mass percent and volume percent?
Mass percent refers to mass in grams, volume percent to volume. For alcohol, for example, the two figures differ clearly.
How does the mixing cross work?
Target minus the lower concentration gives the parts of the higher solution, higher concentration minus target gives the parts of the lower one. Together the parts make up the total mass.
Sources and legal basis
- Wikipedia – Massenanteil (DIN 1310, Gehaltsangaben)
- Wikipedia – Mass fraction (chemistry)
- Wikipedia – Mischungskreuz
As of: · Editorial policy
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