This calculator calculates the amounts of two starting solutions of given concentration needed to be mixed together to obtain the final solution requirements. Volume or weight of solution may be used. Just click on the weight or volume button to change to volume or weight units (Click here for illustration). To use water for diluting an Ethanol solution just input its concentration as zero percent (as in no Ethanol content). The calculator uses a table (see Examples) of concentration (% Ethanol by weight or volume) and its equivalent density. Interpolation is used to compute density values that are between the values in the table. The density is then used to compute volume or weight as needed. The Ethanol in water density-concentration table was taken from "Perry's Chemical Engineers' Handbook" by Robert H. Perry, Don Green, Seventh Edition. This calculator has been updated to include the choice of expressing concentration in % Volume Ethanol. Click on the "Use Percent Volume Ethanol" button to switch to % Volume. Please be careful that the correct volume or weight units and the correct concentration expression (% Volume or % Weight) are used in your application.