The calculator takes into account the contraction of ethanol, sugar and water. To the best of our knowledge, no other calculator can do this, since the density measurements required to do so have probably never been made before. Measurements and thus data and formulas exist only from ethanol-water and sugar-water mixtures, but not from a mixture of all three substances together. We made about 40 measurements and found that you can't derive the density of the three-substances mixtures just like that from the density of the two-substances mixtures. If you try that, you miscalculate at say 40%abv and 10% sugar about 6 g/lt density. Ethanol and sugar are insoluble in each other and therefore seem to repel each other in the triple mixture. This increases the volume and decreases the density, respectively. At least that's how we can explain it. We may do more measurements to improve the data. But as it is now, it is at least closer to the truth than with simple calculation methods.
If NaN is displayed for the calculated amount of water, the sugar content is probably so high that the sugar is not soluble, at least in the specified alcohol strength. In any case, the calculator has no data for this range. However, if a result is displayed, this does not mean that the calculated amount of sugar is guaranteed to be soluble in the specified alcohol strength.
If you enter kg, the temperature does not matter. However, if you enter liters, they should either be measured at 20°C / 68°F or the temperature (0-40°C / 32-104°F) should be specified.
The entered %abv 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 refers to 20°C / 68°F by definition.
It is possible to switch between lt, kg, gal, lbs ,fl oz and between °C and °F.

Information about Contraction