When mixing solutions, paints, or cleaners, we often use mix ratios to describe how much of one substance is combined with another. Understanding how to convert a mix ratio into a percent concentration is important for preparing mixtures accurately and safely.
What Percent Concentration Means
Percent concentration tells us how much of the total mixture is made up of the solute (the concentrated substance) compared to the total amount of solution. A higher percentage means there is more concentrate in the mixture, while a lower percentage means there is more solvent (such as water).
Formula
To calculate percent concentration from a mix ratio, use this formula:
Percent concentration = (solute ÷ total mixture) × 100
Where:
- solute = number of parts concentrate
- solvent = number of parts diluent (often water)
- total mixture = solute + solvent
Example
Question:
A cleaning solution uses a 1:4 mix ratio — one part concentrate to four parts water. What is the percent concentration?
Solution:
- Find the total mixture:
Total = 1 part concentrate + 4 parts water = 5 parts - Apply the formula:
Percent concentration = (1 ÷ 5) × 100 = 20%
Answer: The final mixture is 20% concentrate.
Common Ratios and Their Percentages
| Mix Ratio | Solute Parts | Solvent Parts | Total Parts | Percent Concentration |
|---|---|---|---|---|
| 1:1 | 1 | 1 | 2 | 50% |
| 1:2 | 1 | 2 | 3 | 33.3% |
| 1:3 | 1 | 3 | 4 | 25% |
| 1:4 | 1 | 4 | 5 | 20% |
| 1:9 | 1 | 9 | 10 | 10% |
Key Takeaways
- Always add the parts together to find the total mixture.
- The formula (solute ÷ total) × 100 works for any ratio.
- Be careful: some sources mistakenly treat a “1:4 ratio” as 1 ÷ 4 = 25%, but the standard interpretation is 1 part concentrate + 4 parts solvent, giving 20%.