Formula
The chemistry dilution equation
Dilution formulaM₁V₁ = M₂V₂
The equation expresses conservation of solute during dilution. Concentration decreases as total solution volume increases, while the amount of solute remains unchanged.
Worked example
Calculate final concentration
A student dilutes 50 mL of a 2 M solution to a final volume of 200 mL.
- Start with: 2 × 50 = M₂ × 200
- Multiply the initial values: 2 × 50 = 100
- Divide by the final volume: 100 ÷ 200 = 0.5
- The final concentration is 0.5 M
Unit guidance
Keep corresponding units consistent
M₁ and M₂ must use the same concentration unit. V₁ and V₂ must also use the same volume unit. For example, both volumes may be entered in milliliters; conversion to liters is unnecessary when the units match.
Need to calculate concentration from moles and total solution volume? Use the Molarity Calculator.
Chemistry guidance
Common dilution mistakes
- Mixing liters and milliliters in one equation.
- Using solvent volume instead of total final solution volume.
- Entering the unknown value in a field that should remain blank.
- Confusing initial and final concentration values.
- Applying the formula when solute amount changes during the process.
Calculation limits
Assumptions and limitations
The dilution equation assumes that the amount of dissolved solute remains unchanged while solvent is added. Concentration and volume units must also be compatible before values are entered.
The result may not represent real laboratory behavior when a reaction occurs, the solution volume is not additive, evaporation changes the concentration, or the solute is not distributed uniformly.
Related tools
Related chemistry calculators
Calculate solution concentration from solute amount and volume with the Molarity Calculator.
Convert between sample mass and chemical amount with the Mass to Moles Calculator.
Questions and answers
Dilution FAQ
What does M₁V₁ = M₂V₂ mean?
M₁ and V₁ are the initial concentration and volume. M₂ and V₂ are the final concentration and volume after dilution.
Must the volume units be the same?
Yes. Initial and final volume must use the same unit, such as both milliliters or both liters.
Does dilution change the amount of solute?
No. The dilution formula assumes that the amount of dissolved solute remains constant while additional solvent changes the total volume and concentration.