A “fifth” of whiskey is the common term for a standard 750-milliliter bottle of distilled spirits. Understanding the calorie content of this volume is important because alcohol contributes energy to the diet. Since whiskey is typically consumed in measured servings, knowing the complete calorie count of a fifth provides a baseline for tracking consumption and managing overall caloric goals.
Calculating the Total Calories in a Fifth
The vast majority of calories in straight whiskey come exclusively from its alcohol content, or ethanol. Ethanol provides approximately seven calories per gram, which is more than carbohydrates or protein (four calories per gram) but less than fat (nine calories per gram). Unlike beer or wine, distillation removes nearly all carbohydrates, sugars, and fats, leaving the final product as water and alcohol.
A standard fifth contains 750 milliliters (mL) of liquid. For the most common variety, 80-proof whiskey (40% ABV), a 750ml bottle holds approximately 1,500 to 1,560 total calories. This number represents the maximum caloric value of the liquid inside the bottle, regardless of the brand or type of whiskey.
Understanding How Proof Affects Calorie Density
The proof of a whiskey is a direct measurement of its alcohol concentration, which dictates its calorie density. In the United States, proof is defined as twice the percentage of alcohol by volume (ABV). Since ethanol is the primary source of calories, a higher proof whiskey contains more calories per milliliter than a lower proof option.
For instance, 80-proof whiskey (40% alcohol) contains fewer calories per ounce than 100-proof whiskey (50% alcohol). This difference is significant because the additional alcohol replaces water, concentrating the caloric energy. A 100-proof whiskey, often labeled “Bottled-in-Bond,” can push the total calorie count for a 750ml bottle to over 1,650 calories.
Whiskies bottled at cask strength (120 proof or more) represent the highest calorie density. For every 1.5-ounce serving, a 100-proof whiskey contains around 124 calories, while an 80-proof pour contains closer to 96 calories. Consumers must consider the proof when calculating the caloric impact of their chosen spirit.
Calorie Breakdown by Standard Serving Size
Translating the total bottle calories into a practical serving size is the most useful way for consumers to track their intake. The standard serving size for distilled spirits in the U.S. is 1.5 fluid ounces, commonly referred to as a jigger or a shot. A single 1.5-ounce serving of standard 80-proof whiskey contains approximately 96 to 100 calories.
A 750ml fifth of whiskey holds nearly 17 standard 1.5-ounce pours, so the total calorie count is distributed across these servings. If a consumer opts for a smaller 1-ounce pour, the calorie count drops to approximately 65 calories for an 80-proof spirit. These figures apply only when the whiskey is consumed neat or on the rocks, as the addition of water or ice does not affect the calorie content.
Most mixed drinks significantly increase the total caloric intake of the beverage. Common mixers like juice, cola, or sweetened syrups introduce additional carbohydrates and sugars, which can easily double or triple the calories of the final drink. To maintain the lower calorie count of whiskey, it should be paired with zero-calorie options such as club soda or plain water.