How It Works
This calculator works in 4 steps.
Enter solution A
Type concentration C_A and volume V_A.
Enter solution B
Type concentration C_B and volume V_B in the same units.
Combine solute amounts
The calculator computes C_A × V_A + C_B × V_B.
Read the mixture concentration
The calculator divides by V_A + V_B and returns C_mix and the total volume.
The Formula
The formula divides the total solute amount by the total volume.
C_mix = (C_A × V_A + C_B × V_B) / (V_A + V_B)V_mix = V_A + V_B- C_A / C_B:
- Concentrations of solutions A and B
- V_A / V_B:
- Volumes of solutions A and B
- C_mix:
- Mixture concentration
Mixing 300 mL of 70% ethanol with 200 mL of 20% ethanol gives (70 × 300 + 20 × 200) / 500 = 50% v/v, before volume contraction.
Conversion Table
The conversion table gives the mixture concentration for 6 pairs of solutions (concentrations in any shared unit).
| Solution A | Solution B | Total volume | Mixture concentration |
|---|---|---|---|
| 10 @ 50 mL | 2 @ 50 mL | 100 mL | 6 |
| 70 @ 300 mL | 20 @ 200 mL | 500 mL | 50 |
| 1 @ 100 mL | 0.1 @ 400 mL | 500 mL | 0.28 |
| 5 @ 25 mL | 0 @ 75 mL | 100 mL | 1.25 |
| 40 @ 1 mL | 10 @ 3 mL | 4 mL | 17.5 |
| 95 @ 500 mL | 50 @ 500 mL | 1,000 mL | 72.5 |
What Is the Two-Solution Mixing Calculator?
The Two-Solution Mixing Calculator is a tool that returns the concentration of a mixture made by combining 2 compatible solutions of the same solute at different concentrations. The result is the volume-weighted average of the 2 concentrations.
Mixing 2 strengths is common when using up partial bottles or blending a strong and a weak lot. The calculator adds the solute amounts from both solutions and divides by the combined volume. Both concentrations need the same unit, and the volumes are assumed additive.
Common Uses
There are 5 main uses of this calculator.
Partial bottle use
Labs combine leftover stocks of different strengths.
Lot blending
Producers blend a high and a low lot to hit a spec.
Buffer correction
Technicians add stronger buffer to an over-diluted batch.
Alcohol blending
Distillers blend spirits of 2 strengths.
Syrup blending
Food makers blend syrups of different sugar content.