How to calculate calories in a homemade recipe

A homemade dish has no single calorie value. The ingredients, cooking fat and amount of water can vary each time. A repeatable calculation is more useful than choosing a generic dish name and treating it as exact.

The four numbers you need

1. The edible weight of each ingredient.
2. Calories per 100 g for that ingredient in the state you weighed it: raw or cooked.
3. The net weight of the finished food, excluding the pan.
4. The weight of the portion you eat.

For a packaged ingredient, use its own label where available. Tare the scale with the empty container before weighing food.

The calculation

Ingredient calories = ingredient weight × calories per 100 g ÷ 100.

Portion calories = total ingredient calories × portion weight ÷ finished recipe weight.

This assumes the counted ingredients remain in the food. Discarded cooking fat or liquid creates uncertainty, and unevenly distributed ingredients can make individual portions differ.

A worked example

Using our reference entries, 300 g of plain cooked rice contributes 390 kcal, 200 g of cooked skinless chicken breast contributes 330 kcal, and 10 g of canola oil contributes 88.4 kcal. The total is 808.4 kcal.

If the finished mixture weighs 510 g, a 250 g portion contains approximately 396.3 kcal. If adding only water increases the finished weight to 600 g, the same 250 g portion contains approximately 336.8 kcal. The whole recipe still contains the same energy. This is a calculation example, not a recommended portion.

Keep raw and cooked records consistent

Rice absorbs water; meat can lose water. A cooked weight needs a cooked-food record. There is no universal conversion factor for every recipe. Write down the ingredients and finished weight so that a saved recipe can be updated when your method changes.

Avoid missing or counting ingredients twice

Include cooking oil, sauces, drinks and sides. If a selected mixed-dish recipe already includes oil, do not add that same oil again. A photo can help start a log, but it cannot reveal every hidden ingredient. See the photo calorie estimate guide.

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Sources for this guide

• FoodData Central: data documentation — USDA (See source)