How do you calculate calories and macros in a recipe?
In short: Weigh or measure ingredients accurately before or during preparation, look up the energy and macros per 100 g for each one, scale each to the weight you used and add them up for the whole recipe. Divide the total by the number of servings, or by the cooked weight if people will serve themselves different amounts. Match raw weights to raw database entries, and count the oil, sauces and toppings.
1 min 12 s videoCaptions onUpdated 9 October 2026
The method in four steps
- Write down every ingredient with its weight in grams, weighed before or during preparation and before cooking, rather than only at the moment it is added. That includes the oil in the pan, the stock and the cheese grated on top.
- Find the energy, protein, carbohydrate and fat per 100 g for each one. Food composition values are estimates and can vary between products, preparation methods and databases, so where you can, use the specific product's nutrition label or an appropriate verified food composition database entry. Pick the entry that matches the state you weighed it in, such as dry rice or raw chicken.
- Multiply each value by the grams used and divide by 100. Then add the rows together to get the whole recipe.
- Divide the totals by the number of servings, or by the cooked weight (see below).
The arithmetic is simple. Nearly every error I see comes from the inputs, not the sums.
A worked example
A chicken and rice bake for four people. The values per 100 g are typical figures, and your database will differ a little.
| Ingredient | Amount | kcal per 100 g | kcal | Protein (g) |
|---|---|---|---|---|
| Chicken breast, raw | 600 g | 120 | 720 | 135 |
| Basmati rice, dry | 300 g | 350 | 1050 | 21 |
| Onion, raw | 150 g | 40 | 60 | 2 |
| Chopped tomatoes, canned | 400 g | 20 | 80 | 4 |
| Olive oil | 30 g | 884 | 265 | 0 |
| Water | 600 mL (approximately 600 g) | 0 | 0 | 0 |
| Whole recipe | 2175 | 162 |
Divide by four equal servings and each is about 544 kcal (about 2275 kJ) and 40.5 g of protein.
The 30 g of olive oil contributes approximately 12% of the recipe's total energy, showing why cooking fats should be included in recipe calculations.
The energy calculated from displayed protein, carbohydrate and fat values may differ slightly from the database's stated energy because of rounding and the energy contributions of other components, such as fibre.
Servings or cooked weight
Dividing by servings works when the portions are equal, like a tray bake cut into four. For a pot of chilli or a batch a client scoops from all week, weigh the finished dish instead and work per 100 g.
The raw ingredients plus the 600 mL of water weigh 2080 g in total, and the baked dish weighs 1800 g because some water cooked off.
Water evaporation changes the weight and energy density of the finished dish, but does not itself remove calories. In this example, assuming no energy-containing ingredients are lost or added during cooking, the recipe remains approximately 2175 kcal. If fat, cooking liquid or other ingredients are discarded, the calculation may need adjusting.
kcal per 100 g cooked = 2175 ÷ 1800 × 100 = about 121 kcal A 400 g bowl = 2175 ÷ 1800 × 400 = about 483 kcal
Write the cooked weight on the recipe. A client who knows 100 g of the dish is 121 kcal can log any portion by weighing it.
Where recipe numbers go wrong
- Raw weight, cooked entry. Dry rice is roughly 350 kcal per 100 g and boiled rice roughly 130, although values vary by database and preparation method. Pair a dry weight with the boiled entry and the rice comes out at only about 40% of its real energy.
- Cups and spoons. A cup of oats and a cup of honey can have very different weights. Volume measures are not interchangeable between ingredients, which is why weighing in grams improves consistency. Why grams and cups give different results explains the conversion.
- Fat that leaves or arrives. Mince fat poured off, oil soaked up when frying, a marinade thrown away. You have to estimate these, so note what you assumed.
- The wrong entry. "Chicken" can mean raw breast or roasted thigh with skin. See why nutrition databases differ before you trust the first result.
For a quick one-off check, the free recipe nutrition calculator does the sum for you. For recipes that go into clients' meal plans, build them somewhere the numbers stay attached to the recipe.
How to do it in Foodzilla
Foodzilla adds up the ingredients from the database you pick, and the nutrition panel updates as you add each one. The video builds a recipe from scratch.
- 1Go to Recipes and choose New Recipe. On the Details tab, enter the Recipe Name and set the Number of servings under Serving Size.
- 2Open the Ingredients tab. Leave Ingredient & Nutrition Source on Use Foodzilla Data and choose Add Ingredients.
- 3Search for each food, change the database in the dropdown if you want a specific one, and tap a result to add it. Set the amount and unit, weighing in grams where you can, then press Add 1 ingredient, or Add 5 ingredients if you picked several.
- 4To add a whole ingredient list at once, choose Bulk Add, paste one ingredient per line with its quantity, and choose Match ingredients.
- 5Check the nutrition panel (on a small screen, choose View Nutrition Details). Switch between One Serving and All Servings to see the per-serving figures and the recipe total, then choose Save Recipe.
Good to know
- Pay attention to energy-dense ingredientsOils, nuts, seeds and cheese can make a substantial contribution to a recipe's energy content. For example, 10 g of olive oil provides approximately 90 kcal. Weigh these ingredients carefully, while recognising that small variations in very low-energy ingredients, such as salad leaves, generally have less impact on the total.
- Use your own totals sparinglyIf you have lab or label figures for a whole dish, Use My Own Data lets you type the totals for the whole recipe. Foodzilla's meal plan auto-generator leaves those recipes out, so build from ingredients when you can.