Alligation Calculator
Enter the higher concentration, the lower concentration, and the target between them. The calculator returns the mixing ratio, and the amount of each when you give a total quantity. It assumes quantities add linearly on the same concentration basis.
Last updated: September 26, 2026
Frequently asked questions
What is alligation?
Alligation is a shortcut for finding the ratio in which two ingredients of different concentrations must be mixed to reach a concentration in between them.
How is alligation different from dilution?
Dilution typically starts from a single stock and adds a diluent of zero concentration. Alligation mixes two sources that both have nonzero concentrations and finds the proportions of each.
How do the parts work?
Higher parts = target − lower, and lower parts = higher − target. For 20% and 5% with a 10% target, that is 5 parts of 20% to 10 parts of 5%, a ratio of 1:2.
Why must the target lie between the two concentrations?
A mixture of two solutions can only land between their concentrations. A target outside that range is impossible by mixing alone.
Can I mix percent by mass with percent by volume?
No. All concentrations must use the same basis, and volume-based mixing assumes volumes are additive.
Is this a dosing or compounding tool?
No. It performs the alligation arithmetic only and is not intended for medication compounding or hazardous chemical mixing.