Mixing two solutions of the same solute
When two solutions contain the same solute on the same concentration basis, their solute amounts can be added. Under an additive-volume model, final concentration is the total solute amount divided by total volume.
The target-blend mode solves the two source volumes for a desired concentration between two different source concentrations.
How to use the solution mixing calculator
- Choose a mode: Calculate final concentration or volumes for a target blend.
- Use one concentration basis: Both sources and the target must use the same solute and concentration unit.
- Enter volumes: Use the same volume unit throughout.
- Calculate: Review the default or updated blend and its assumptions.
Formula and variables
For target total volume Vₜ, V₁ = Vₜ(Cƒ − C₂)/(C₁ − C₂) and V₂ = Vₜ − V₁.
C₁V₁ + C₂V₂ = Cƒ(V₁ + V₂)- C₁ — Solution 1 concentration
- First source concentration
- V₁ — Solution 1 volume
- First source volume
- C₂ — Solution 2 concentration
- Second source concentration
- Cƒ — Final concentration
- Concentration after mixing
Equal-volume mixture
Mix 100 mL of 1.0 M solution with 100 mL of 0.2 M solution.
- Solution 1
- 1.0 M, 100 mL
- Solution 2
- 0.2 M, 100 mL
- Cƒ = (1.0 × 100 + 0.2 × 100)/(100 + 100)
Result: Cƒ = 0.6 M.
Equal source volumes give the arithmetic mean of the two concentrations under this model.
Understanding your results
The result is volume weighted
The larger source volume contributes more strongly to final concentration.
- The final value lies between the two source concentrations.
- Equal volumes give their arithmetic mean.
- The target must lie between two different sources.
- Percent and molarity are not interchangeable concentration bases.
Assumptions
- Both solutions contain the same solute on the same concentration basis.
- Volumes are additive.
- Mixing causes no reaction, precipitation, evaporation, or solute loss.
Limitations
- Does not convert between molarity, mass fraction, volume percent, or other concentration bases.
- Does not model density, volume contraction, reactions, or nonideal activity.
- Accurate preparation may require calibrated volumetric equipment.
Common mistakes
- Using different concentration units or bases.
- Using the formula for reacting solutes.
- Requesting a target outside the source concentration range.
- Assuming real volumes are always exactly additive.
Practical use cases
Laboratory blending
Estimate a same-solute blend before final volumetric adjustment.
Chemistry coursework
Apply n = CV and conservation of solute amount to two sources.
Frequently asked questions
Can I mix percent and molar concentrations?
No. Convert all concentrations to one compatible basis first.
Is this the same as dilution?
Dilution commonly combines stock with zero-concentration solvent; this calculator allows two nonzero source concentrations.
Sources and review
- Molarity — OpenStax Chemistry 2e. Accessed 2026-07-14.
Reviewed 2026-07-14.