Concentration Calculator

Last updated: June 2026

Use this concentration calculator to calculate molar concentration, mass concentration, mass percentage and mass/volume percentage. A separate converter changes between mol dm−3 and g dm−3 using molar mass.

Key takeaway: Concentration compares an amount of solute with the amount of solution. Always identify whether the question uses moles, mass, solution mass or solution volume before selecting a formula.
How to use this concentration calculator
  1. Choose the concentration type that matches the question.
  2. Enter the required amount, mass or volume.
  3. Select the volume unit where applicable.
  4. Press Calculate to see the conversion, substitution and answer.
  5. Use the converter when changing between mol dm−3 and g dm−3.

What is concentration?

Concentration describes how much solute is present in a particular amount of solution. A concentrated solution contains more solute per unit amount of solution than a dilute solution.

Molar concentration

c = n / V

Molar concentration uses amount in moles and solution volume in dm3. It is commonly used in titration, equilibrium, acid–base and mole calculations.

Mass concentration

mass concentration = mass of solute / volume of solution

When mass is measured in grams and volume is measured in dm3, the unit is g dm−3.

Mass percentage concentration

mass % = mass of solute / mass of solution × 100%

The denominator is the total mass of the solution, not merely the mass of solvent.

Mass/volume percentage concentration

m/v % = mass of solute in g / solution volume in mL × 100%

A 5.00% m/v solution contains 5.00 g of solute in every 100 mL of solution.

Converting between molar and mass concentration

mass concentration = molar concentration × molar mass
molar concentration = mass concentration / molar mass

Molar mass is therefore required whenever you convert between mol dm−3 and g dm−3.

Concentration after dilution

Dilution lowers concentration by adding solvent while keeping the transferred amount of solute unchanged:

c1V1 = c2V2

Use the dedicated Dilution Calculator when the question asks for stock volume, final volume or concentration after dilution.

Worked examples

Molar concentration

A solution contains 0.200 mol in 500 cm3. Since 500 cm3 = 0.500 dm3:

c = 0.200 / 0.500 = 0.400 mol dm−3

Mass concentration

A solution contains 10.0 g in 250 cm3. Since 250 cm3 = 0.250 dm3:

mass concentration = 10.0 / 0.250 = 40.0 g dm−3

Mass percentage

mass % = 8.00 / 200 × 100% = 4.00%

Mass/volume percentage

m/v % = 2.50 / 100 × 100% = 2.50%

Common exam traps

Convert cm3 to dm3. Divide by 1000 before using c = n / V or calculating g dm−3.
Do not confuse mol dm−3 with g dm−3. One uses amount in moles; the other uses mass in grams.
Use the mass of the whole solution for mass percentage. Do not use only the solvent mass.
Use final solution volume. When a solution is made up to a mark, use the final volume rather than the volume of solvent added.

Frequently asked questions

Is concentration the same as molarity?

Molarity is one type of concentration. It specifically measures moles of solute per dm3 of solution.

Can I enter volume in mL?

Yes. The calculator converts mL or cm3 to dm3 when required.

Why is molar mass needed for concentration conversion?

Molar mass connects moles and grams, allowing mol dm−3 to be converted into g dm−3 and vice versa.

What is the difference between mass % and m/v %?

Mass percentage compares solute mass with total solution mass. Mass/volume percentage compares solute mass in grams with solution volume in millilitres.

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