Concentration Calculator
Enter solute mass, solution volume, density, and optional molar mass to see common concentration metrics at a glance.
Use 1.0 g/mL for water-like solutions unless otherwise known.
Needed to compute molarity. Leave blank if molarity is not required.
Mass percent
1%
Parts per million (ppm)
10,000
mg per mL
10 mg/mL
Molarity
0.1711 mol/L
Requires molar mass input.
With solute mass 5.0 g in 0.5 L solution (density 1.0 g/mL), mass percent is 1%, concentration is 10,000 ppm, and 10 mg/mL. If molar mass is supplied, molarity is 0.1711 mol/L.
How to Use This Calculator
Measure solute mass
Weigh the solute you have dissolved (in grams).
Record solution volume
Enter the final volume of solution prepared in liters. Include any solvent used to reach the mark.
Provide solution density
For most aqueous solutions use 1.0 g/mL. Supply a more accurate density if known.
Optional: add molar mass
Provide molar mass to compute molarity in addition to mass-based units.
Formula
mass % = (mₛ / mₛₒₗ) × 100
ppm ≈ (mₛ / mₛₒₗ) × 10⁶
Molarity = (mₛ / M) / V
mₛ is solute mass, mₛₒₗ is solution mass (density × volume), M is molar mass, and V is solution volume in liters.
Example
5 g NaCl dissolved to 500 mL (density 1 g/mL) gives 1% mass fraction, 10,000 ppm, 10 mg/mL, and 0.171 mol/L (M = 58.44 g/mol).
Full Description
There are many ways to express concentration. Laboratory work often requires switching between mass-based units (percent, mg/mL, ppm) and molarity for stoichiometric calculations. This calculator centralizes those conversions.
Provide solute mass, solution volume, density, and optionally molar mass. The tool computes several concentrations simultaneously so you can report the most appropriate unit or cross-check manual calculations.
The calculations assume additive volumes and uniform density. For viscous or highly concentrated solutions, measure density experimentally for improved accuracy.
Frequently Asked Questions
Do I need density?
Density enables conversion between mass percent and ppm. If unknown, assume 1.0 g/mL for dilute aqueous solutions.
What if volume changes after dissolution?
Always measure the final volume after the solute dissolves. Volumes can contract or expand slightly depending on the solute.
Why is molarity optional?
Molarity requires molar mass. If you only need mass-based units, leave it blank and the calculator will skip that output.
Can I enter volume in mL?
Convert to liters before entering. Alternatively, divide your milliliter value by 1000.
Is ppm the same as mg/L?
For water-like densities, 1 ppm ≈ 1 mg/L. The calculator accounts for density to provide a general solution mass basis.