Solution Concentration Calculator
Calculate solution concentration in w/v percent, g/L and ppm (mg/L). Enter solute mass in grams and solution volume in millilitres.
How to use this tool
- Enter solute mass and solution volume in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your w/v percent and the full breakdown beneath it.
Common ways to express solution concentration:
- w/v % = grams solute per 100 mL solution
- g/L = grams per litre (= w/v × 10)
- ppm = milligrams per litre (mg/L)
Formula
w/v % = (Solute mass in g ÷ Solution volume in mL) × 100
Concentration (g/L) = Solute mass (g) ÷ Solution volume (L)
Concentration (ppm) = Concentration (mg/L) = g/L × 1000
How it works
This tool expresses a solution's concentration in three common laboratory units from the same two inputs: solute mass in grams and solution volume in millilitres. Weight-per-volume percent (w/v %) is grams of solute per 100 mL; g/L is the same ratio scaled to one litre; ppm here is mg per litre (mg/L), which is numerically identical to g/L × 1000 and valid for dilute aqueous solutions.
The formula assumes the stated volume is the final solution volume, not the solvent volume added. For highly concentrated solutions, the ppm = mg/L approximation assumes solution density is approximately 1 kg/L (dilute aqueous assumption) and may introduce small errors.
Worked example
- 5 g of solute dissolved in 100 mL of solution.
- w/v % = (5 ÷ 100) × 100 = 5.0%.
- Solution volume in litres = 100 mL ÷ 1000 = 0.1 L; concentration = 5 g ÷ 0.1 L = 50.0 g/L.
- ppm (mg/L) = 50.0 g/L × 1000 = 50,000 mg/L.
Concentration is 5.0% w/v, 50.0 g/L, and 50,000 ppm (mg/L).
Common mistakes to avoid
- Using the mass of the solvent instead of the total solution volume in the denominator; w/v % is solute mass divided by solution volume, not solvent volume.
- Confusing ppm as mg/L (mass/volume, used in aqueous chemistry) with ppm as mg/kg (mass/mass, used in environmental soil analysis), which differ by the density of the solution.
- Neglecting to convert mL to L when computing g/L, producing a result 1000x too high and incorrectly labeled as g/L when it is actually g/mL.
Key terms
- w/v percent (w/v %)
- Weight-per-volume percent: grams of solute per 100 mL of solution. A 5% w/v NaCl solution contains 5 g of NaCl in every 100 mL.
- g/L (grams per litre)
- Mass concentration of solute expressed per litre of solution; convenient for lab-scale calculations.
- ppm (parts per million)
- For dilute aqueous solutions, 1 ppm = 1 mg per litre of solution, assuming the solution density is approximately 1 kg/L.
- Solute
- The substance dissolved in a solution; typically the minor component (e.g., salt or sugar in water).
- Solvent
- The substance doing the dissolving; typically the major component (e.g., water in aqueous solutions).
Frequently asked questions
- What does w/v percent mean?
- Weight/volume percent (w/v %) is the mass of solute (g) per 100 mL of solution. A 5% NaCl solution has 5 g of NaCl in every 100 mL.
- How do I convert between ppm and g/L?
- 1 g/L = 1000 mg/L = 1000 ppm (in dilute aqueous solutions where 1 L ≈ 1 kg).