Grams to calories converter
Pick a nutrient, then convert its grams to calories and kilojoules, or a calorie target back to grams.
That's 1.26× as much energy as an apple, while a snack is 1.67× more. That is 6 % of a 2,000 kcal day.
What it means
How much energy is that?
Atwater factors as used on food labels. Real foods vary a little, and fibre is often counted at 2 kcal/g or not at all.
Every unit
That food energy in every unit
Learn
Three things worth knowing
-
4, 4, 9, 7
Protein and carbs 4 kcal/g, fat 9, alcohol 7. A 30 g protein shake scoop is 120 kcal of protein.
-
Atwater’s bomb calorimeter
Wilbur Atwater burned foods and measured digestion in the 1890s; his averaged factors are still on every label.
-
Calories and kilocalories
The “Calories” on food are kilocalories. 2,000 Calories a day is 2,000 kcal, about 8,400 kJ.
Shortcuts
Popular food energy conversions
Background
About calories from macronutrients
Food labels work out calories from the grams of each nutrient with the Atwater factors: 4 kcal per gram of protein or carbohydrate, 9 per gram of fat and 7 per gram of alcohol.
A “Calorie” on a US label is a kilocalorie; European labels also give kilojoules, 4.184 kJ per kcal.