Calories Per Serving Calculator
Split a recipe's total energy across its servings — in both calories and kilojoules, with the per-100 g figure that matches a food label.
Add up the energy of everything that goes into the dish, divide by the number of servings, and you have the per-serving figure.
How the calories per serving calculator works
Add up the energy of everything that goes into the dish, divide by the number of servings, and you have the per-serving figure. The per-100 g figure is the one to compare against packaging, since that is how labels are written, and it needs the finished weight of the dish rather than the sum of the raw ingredients — some water evaporates in cooking, which concentrates the energy per gram without changing the total.
Calories and kilojoules are the same quantity in different units: one kilocalorie is 4.184 kilojoules. Labels in Australia and much of Europe lead with kilojoules, while the US and UK lead with kilocalories.
Formula: per serving = total energy ÷ servings; per 100 g = total ÷ finished weight × 100
Worked examples
| Inputs | Calories per serving | Note |
|---|---|---|
| 2,400 kcal across 4 servings | 600 kcal | 600 kcal each, 150 kcal per 100 g |
| A tray bake, 3,200 kcal in 12 pieces | 267 kcal | 267 kcal a piece |
| A soup, 900 kcal in 6 bowls | 150 kcal | 150 kcal a bowl, low per 100 g |
FAQFrequently asked questions
How do I work out calories per serving?
Add up the energy of every ingredient, then divide by the number of servings.
Why is the per-100 g figure different?
Because it uses the finished weight after cooking. Water evaporates, so a reduced sauce is more energy-dense per gram even though the total has not changed.
How do I convert calories to kilojoules?
Multiply by 4.184. A 600 kcal serving is 2,510 kJ.
Is a Calorie the same as a calorie?
On food labels, yes — the capital-C Calorie is a kilocalorie, a thousand of the small ones used in physics.
Does cooking change the calories?
Not meaningfully for the total, though draining fat or losing liquid changes what ends up on the plate.
Where these figures come from
- US FDA — Safe Minimum Internal Temperatures — the internal temperatures the roasting calculator targets
- NIST SP 811 — Guide for the Use of the International System of Units — the exact weight and volume conversions used throughout
- UK Food Standards Agency — food safety and labelling standards
Last checked: September 2026. Baking ratios follow standard baker's percentage practice; roasting guidance follows published safe internal temperatures.