The contraction is taken into account.
If you enter kg, the temperature does not matter. However, if liters are entered, they should either be measured at 20°C / 68°F or the temperature (0-40°C / 32-104°F) should be specified.
The entered vol% must refer to 20°C / 68°F. So you should not enter the %abv reading and the temperature when measuring the %abv, but the temperature when measuring the liters. This calculator does not replace the calculator Alcoholmeter Temperature Correction. %abv always refer to 20°C / 68°F according to the definition.
Negative quantities can also be entered. This way you can calculate for example how the composition in the boiler changes when you have distilled off a part of the liquid.

Information about Contraction