You’ll get about the same amount of calories from either straight whiskey or vodka. It really depends on the concentration of alcohol that's in your liquor. You'll also see proof listed on the label, which is a number that is double the alcohol percentage. But it all comes down to the grams of alcohol to calculate calories. All alcohol has 7 calories per gram. So the more grams of alcohol that are in your liquor, the higher the alcohol percentage, the higher the proof and the more calories you’ll get.
If your whiskey or vodka is 40 percent alcohol, or labeled as 80 proof, you’ll get less than 100 calories from the 14 grams of alcohol in a 1.5-ounce shot. Having the same amount of 45 percent whiskey or vodka, which is known as 90 proof, will give you 110 calories from the nearly 16 grams of alcohol. A 50 percent whiskey or vodka liquor, or 100 proof, has closer to 125 calories from nearly 18 grams of alcohol, in that same 1.5-ounce shot.