Calorie Calculator (Macros)

Convert protein, carbs and fat grams into kilocalories using the 4-4-9 rule, with a food quick-reference table.

g
g
g
Total energy735 kcalFrom protein: 120 · From carbs: 480 · From fat: 135
Common foods per 100 g
Foodkcal
Cooked white rice130
Boiled egg155
Grilled chicken breast165
Grilled salmon208
Rolled oats (dry)389
Almonds579
White bread265
Cooked pasta158
Boiled potato87
Apple52
Banana89
Avocado160
Dark chocolate 70%604
Whole milk61

What is it

Every gram of macronutrient carries a known energy price: protein and carbs deliver about 4 kcal per gram, fat about 9. Type in your grams and this tool shows the total kilocalories at once — the same math nutrition labels run on the back of every package.

Notes & fun facts

Ever wondered why a spoonful of oil ruins an otherwise light salad? Fat packs 9 kcal per gram — more than double carbs — so 10 g of dressing costs you as much as 50 g of rice. That asymmetry is why calorie tracking quietly punishes the bottle, not the bowl.

Origin & history

These 4/4/9 factors come from American chemist Wilbur Olin Atwater, who in the 1890s burned food samples in a bomb calorimeter and measured how much heat each macronutrient released. His 1896 tables became the Atwater system, still the basis of food labels worldwide.

Keep a kind heart, hold integrity as your foundation, and cherish warm love; may the world know peace and humanity live in harmony.
持善良之心,守正直之本,怀温暖之爱;愿世界和平,人间祥和。