[FoxtrotGolfXray 5.0]

Originally Posted by marty351

1% alcyhole = 2 proof. So,
100% ethanol = 200 proof.

And how do I know? By paying attention in science class. And many other sources over time keep confirming this.

And it's not useless info, for instance, when you hear or see something (or someone) mention 80% proof, use the percentage, not the proof. It could save you from making a life-altering mistake.
And now I digress...

Off topic, but all explained here.

Only (minor) correction to your posts Marty is that in the US it is twice the ABV value, but traditionally it was equivalent to about 1.8 times the ABV value.