Explanation
Calories in a homemade serving
Add up the calories of every ingredient, then share the total out. Split it into equal servings, rebuild the total from a per-serving figure, or weigh the cooked dish and your portion for an estimate that does not depend on cutting equal slices.
e = E ÷ n
| e | Calories in the portion (kcal) |
|---|---|
| E | Whole recipe (kcal) |
| n | Servings (servings) |
A 1,000 kcal recipe split 4 ways
| Whole recipe | 1,000 |
|---|---|
| Servings | 4 |
| Result | 250 kcal |
e = E ÷ n = 1,000 kcal ÷ 4 = 250 kcal
E = e × n
| E | Calories in the whole recipe (kcal) |
|---|---|
| e | Per serving (kcal) |
| n | Servings (servings) |
4 servings of 250 kcal each
| Per serving | 250 |
|---|---|
| Servings | 4 |
| Result | 1,000 kcal |
E = e × n = 250 kcal × 4 = 1,000 kcal
e = E × m ÷ M
| e | Calories in the portion (kcal) |
|---|---|
| E | Whole recipe (kcal) |
| M | Cooked weight (g) |
| m | Your portion (g) |
A 200 g portion of an 800 g, 1,000 kcal batch
| Whole recipe | 1,000 |
|---|---|
| Cooked weight | 800 |
| Your portion | 200 |
| Result | 250 kcal |
e = E × m ÷ M = 1,000 kcal × 200 g ÷ 800 g = 250 kcal
Diagram of this result
Counting servings, the grid shows one cell per serving with your serving highlighted, or the equation adds equal servings into the whole. Weighing a portion, the bar splits the cooked batch into your portion and the rest.
The calories, servings and weights in the diagram are the same numbers stated in the answer and the steps.
Common mistakes
Weigh the dish after cooking. Water evaporates, so a stew can lose weight without losing calories, and dividing by the raw weight underestimates each gram. Counting servings only works if the servings really are equal.
Assumptions and limits
Servings and cooked weight must be more than zero; calories and portions may be zero, and servings may be fractional. A portion heavier than one batch is allowed, for example when two batches are combined. Estimates assume the food is evenly mixed and the ingredient totals are accurate. Answers are shown to the nearest kilocalorie. Educational estimate only, not dietary advice.
Are Calories and kcal the same?
Yes. The Calorie with a capital C on food labels is one kilocalorie (kcal). One kcal is 4.184 kJ, so 300 kcal is about 1,255 kJ.
Sources
Ingredient nutrition data: USDA FoodData Central, https://fdc.nal.usda.gov/. Measurement conventions: NIST SP 811, https://www.nist.gov/pml/special-publication-811.