Recipe Calorie Calculator

How the calculator works

A recipe’s calories are the sum of its ingredients’ calories. Nothing is created in the oven. The calculator finds each ingredient in USDA FoodData Central, converts the amount you typed to grams, and applies the USDA energy value:

calories in a line = grams / 100 x calories per 100 g

calories per serving = total calories / servings

It reads weights directly. For cups and spoons it uses the USDA weight of a cup of that particular food, because a cup is not a fixed weight: a cup of flour is 125 g and a cup of honey is 339 g.

Worked example

A plain butter cake that makes 12 pieces.

1. 2 cups all-purpose flour: 250 g x 364 / 100 = 910 calories.
2. 1/2 cup salted butter: 113.5 g x 717 / 100 = 814 calories.
3. 3/4 cup sugar: 150 g x 387 / 100 = 581 calories.
4. 2 large eggs: 100 g x 143 / 100 = 143 calories.
5. 1/2 cup whole milk: 122 g x 61 / 100 = 74 calories.
6. 1 teaspoon baking powder: 2 calories.
7. 1/4 teaspoon salt: 0 calories.

Total: 2,524 calories. Per piece: 2,524 / 12 = 210.

Cut the same cake into 16 smaller pieces and each is 158 calories. Cut it into 8 and each is 316. The cake has not changed. The serving count is the single biggest lever on a per serving figure, which is why two versions of the “same” recipe online can disagree so widely.

Where the calories come from

Calories come from three things: carbohydrate, protein and fat. The general factors used for food labels are 4 calories per gram for carbohydrate and protein, and 9 for fat. Fat carries more than twice as much per gram, which is why the fats in a recipe count for so much.

In the cake, the totals are 349 g of carbohydrate, 43 g of protein and 108 g of fat. Applying 4, 4 and 9:

• Carbohydrate: 349 x 4 = 1,395 calories, 55 percent
• Fat: 108 x 9 = 972 calories, 38 percent
• Protein: 43 x 4 = 173 calories, 7 percent

Butter is about 15 percent of the batter by weight (113.5 g of 742 g) and close to a third of its calories.

The dense ingredients

From the USDA records the calculator uses, per tablespoon:

• Olive oil: 119 calories
• Butter: 102
• Honey: 64
• Brown sugar: 52
• Maple syrup: 52
• Granulated sugar: 49
• All-purpose flour: 28
• Whole milk: 9

And per cup:

• Olive oil: 1,909 calories
• Butter: 1,628
• Honey: 1,031
• Granulated sugar: 774
• White rice, uncooked: 675
• All-purpose flour: 455
• Rolled oats: 307
• Whole milk: 149

Two things stand out. Oils and butter sit far above everything else, so a “glug” of oil that measures 3 tablespoons adds about 360 calories that never made it into the recipe. And a cup of honey has more calories than a cup of sugar, because a cup of honey is so much heavier.

Raw weight, cooked weight

Enter ingredients as they go into the recipe, raw and before cooking. The calories are counted at that point and stay with the dish.

What cooking changes is the weight. A loaf loses water in the oven. Rice and pasta take water in: the USDA figure of 675 calories is for a cup of uncooked rice, which cooks up to about three times the volume. If you enter “1 cup rice”, the calculator assumes uncooked.

The exception is fat you do not eat. Oil left in a frying pan, or fat poured off browned meat, is in the total but not on your plate. If that is a large amount, measure what is left and subtract it from the line.

Getting a figure you can trust

Weigh the dense ingredients. An error of a tablespoon of oil is 119 calories. An error of a tablespoon of flour is 28.

Count the cooking fat. The oil for the pan is part of the recipe even when the ingredient list does not mention it.

Check the servings. Decide what a serving is on the plate, then count how many the recipe makes.

Read “Not counted”. A line the calculator could not match or weigh contributes nothing. For a main ingredient, give a weight in grams and it will usually go through.

Use the right butter. Salted and unsalted butter have the same calories, 717 per 100 g. They differ only in sodium.

Tips and common mistakes

Do not divide by the number of people who ate it. Divide by the number of servings the batch makes, including leftovers.

Count toppings and glazes. Frosting, a drizzle of honey and the butter on the toast are often left off.

Remember drinks made from recipes. A cup of whole milk in a smoothie is 149 calories before anything else goes in.

Compare like with like. A recipe figure “per 100 g” and a figure “per serving” cannot be compared until you know the weight of the serving.

Re-run the total when you change an ingredient. Swapping half the butter for something else changes the largest line in most baking recipes, and the calculator will show by how much.