This calculator will help you formulate a percent solution to determine the concentration of the solute to solution needed. Translated, this means you can calculate the amount to add in order to reach a specific percentage. This calculator uses gallons as its basis of total solution.

This is actually a commonly used calculation when determining how much of a concentrated pesticide, herbicide, fertilizer or cleaning product to add to water or other solution. So if you want to know how much bleach to add to a gallon of water to make a 10% disinfectant solution, we’re here to help.

Keep in mind that if you are wanting a 1%, 2% (etc) percent solution and want to be as precise as possible, you should subtract the amount of solute you will be adding from the solution. For example: If, to reach a 1% percent solution of a pesticide, the calculator suggests adding two tablespoons of the pesticide to a gallon of water, you should also reduce your gallon of water by two tablespoons.

**Quick Reference**

**1% per one gallon** = 1.28 Ounces (oz) or 2.56 Tablespoons (Tbsp)

**2% per one gallon** = 2.56 Ounces (oz) or 5.12 Tablespoons (Tbsp)

**1% per 2 gallons** = 2.56 Ounces (oz) or 5.12 Tablespoons (Tbsp)

**2% per 2 gallons** = 5.12 Ounces (oz) or 10.24 Tablespoons (Tbsp)

**10% per one gallon** = 12.8 Ounces (oz) or 1.58 Cups (c)