How to Calculate Calories in a Recipe by Weighing the Pot

By Eric Parker, founder of TrueCal. Published October 9, 2026. Sources checked October 9, 2026.

Written with AI assistance from the cited studies. Every claim was checked against its source. Editorial policy.

Key takeaways

To calculate calories in a recipe, add up the calories of every raw ingredient, weigh the whole cooked dish and divide the total by that weight. Then weigh your portion and multiply it by the calories per gram.
Each ingredient's number comes from its calories per 100 grams. USDA FoodData Central lists raw 85 percent lean ground beef at 215 calories per 100 grams, so 500 grams of it is 1,075 calories.⁷
Divide by the cooked weight, not the raw weight, because cooking changes what food weighs. In USDA's cooking yield study, medium fat ground beef browned as crumbles came out at 67 percent of their raw weight, and most of what left the pan was water.¹
Count the oil. Fillion and Henry's 1998 review of frying found that food takes up some of the fat it cooks in, which raises its energy density.³
Work the recipe out once and keep its calories per gram. Every later serving is just a scale reading times that number.

How to calculate calories in a recipe

You need a kitchen scale, the raw weight of each ingredient and one more weighing at the end. The steps go in this order.

Weigh the empty pot before you start and write the number down.
Weigh each ingredient raw as it goes in, including the oil in the pan. For canned food, weigh what you actually add, drained or not.
Find each ingredient's calories per 100 grams on its label or in USDA FoodData Central. Multiply by the grams you used and divide by 100.
Add the ingredient calories together. That's the calories in the whole recipe. If you drain off fat or leave oil behind in the pan, the calories in it leave the dish too, so this total runs high.¹³
When the dish is done, weigh the full pot and subtract the empty pot. That's the cooked weight.
Divide the recipe calories by the cooked weight to get calories per gram of cooked food.
Weigh your portion and multiply it by calories per gram.

Where the ingredient numbers come from

FoodData Central is USDA's food composition database, run by the Agricultural Research Service. Its SR Legacy records give raw ingredients such as onions and ground beef per 100 grams, which is the form a recipe starts in. Search for the ingredient in the state you weighed it, raw onion for raw onion, drained beans for drained beans.⁴⁶⁷

For packaged ingredients, the label works just as well. Use the per 100 gram column if there is one, or divide the calories by the serving weight in grams.

How to calculate calories in homemade food, a worked pot of chili

Here's the method on one pot of beef and bean chili. Every ingredient number comes from a USDA FoodData Central record, listed in the sources below. USDA weighs one can of drained kidney beans at 266 grams, so two cans is 532 grams.⁵⁶⁷⁹¹⁰

Each row is the raw weight times calories per 100 grams, divided by 100. The beans, for example, are 532 times 124 divided by 100, which is 659.7. Added up, the five ingredients come to 2,075.3 calories and 2,047 grams going into the pot.⁵⁶⁷⁹¹⁰

Now the cooked weight. This number comes from your own scale, so the one here is only an example. Say the empty pot weighed 2,100 grams and the full pot reads 3,850 grams when the chili is done. Subtract, and the chili weighs 1,750 grams.

Divide 2,075.3 calories by 1,750 grams and you get about 1.186 calories per gram of cooked chili. A 350 gram bowl is 350 times 1.186, about 415 calories.⁵⁶⁷⁹¹⁰

The pot weighs 297 grams less than what went into it. If you divided 2,075.3 calories by the raw 2,047 grams instead, you'd get about 1.014 calories per gram and log the same 350 gram bowl at about 355 calories, 60 short.⁵⁶⁷⁹¹⁰

Ingredient, USDA record	Raw weight	Calories per 100 grams	Calories in the pot
Oil, olive, salad or cooking	15 grams	884	132.6⁵
Onions, raw	200 grams	40	80⁶
Beef, ground, 85 percent lean meat, 15 percent fat, raw	500 grams	215	1,075⁷
Tomatoes, red, ripe, canned, packed in tomato juice	800 grams	16	128⁹
Beans, kidney, red, mature seeds, canned, drained solids	532 grams	124	659.7¹⁰
Whole recipe	2,047 grams	Not a single food	2,075.3⁵⁶⁷⁹¹⁰

Why weigh the cooked dish instead of the raw ingredients?

Cooking changes how much food weighs. USDA's Table of Cooking Yields for Meat and Poultry says the changes come from moisture lost to evaporation or drip, water absorbed in boiling, and fat gained or lost. Food databases use those yields to work out values for cooked foods from raw ones when the cooked food hasn't been measured.¹

Ground beef shows how big the change is. In USDA's study, medium fat ground beef browned as crumbles came out at 67 percent of its raw weight. Moisture fell by 27.8 percent of the raw weight and fat by 5.3 percent. Those crumbles were drained in a colander, so some fat left with the drippings. In a chili where nothing is poured off, the fat stays in the pot, and in your total.¹

FoodData Central shows the same thing per 100 grams. Raw 85 percent lean ground beef is 215 calories and 65.66 grams of water. The pan browned crumbles are 256 calories and 55.9 grams of water. With less water in each gram, each gram holds more calories.⁷⁸

USDA's Table of Nutrient Retention Factors, Release 6, uses the same idea. Its true retention method needs the weight of a food before and after cooking along with its nutrient content in both states. The table covers 16 vitamins, 8 minerals and alcohol across about 290 foods, so it tracks how much of a nutrient survives cooking, and calories aren't on its list.²

At home, the scale reading at the end does the job those tables do in a lab. You don't need to know how much water left the pot, only what the pot weighs now.

Count the oil and anything else in the pan

Fat used in cooking ends up in the food. Fillion and Henry's 1998 review of frying found that food inevitably takes up some of the fat it's fried in, raising its energy density, while frying has little or no effect on its protein or mineral content.³

In the chili, 15 grams of olive oil adds 132.6 calories, more than the 200 grams of raw onion it softens, at 80.⁵⁶

Butter, cheese stirred in at the end, cream and sugar all count the same way. If it went into the pot, it goes into the total.

What about pasta, rice and added water?

Weight can go up as well as down. USDA's yields table lists water absorbed in boiling as one cause of weight change. Pasta or rice cooked in a sauce soaks up liquid and makes the pot heavier without adding calories, and the final weighing picks that up.¹

Plain water you add has no calories, so it only shows up in the cooked weight. Broth, stock, milk and wine are ingredients and get weighed and counted like the rest.

Weigh the pot when the dish is finished, the way you'd serve it. If you take a portion out before weighing, weigh that portion and add it back to the cooked weight.

Save the recipe once, then log servings by weight

Calories per gram is the one number to keep. With it, every bowl from that pot is a scale reading and a multiplication.

Write the calories per gram on the container lid or save it with the recipe in your log.
Each time you eat from it, put the bowl on the scale, press tare, serve, and multiply the grams by calories per gram.
If you change an ingredient or an amount, redo the ingredient total.
Reweigh the cooked pot every time you make it, even with the same recipe. USDA's medium fat crumble samples ranged from 64 to 72 percent of raw weight, so one batch can cook down more than the last.¹

Worked example

Two days after making the chili below, you heat up leftovers. Set the bowl on the scale, press tare, and spoon in chili until it reads 280 grams. The pot worked out to about 1.186 calories per gram, so 280 times 1.186 is about 332 calories. There's nothing new to look up, because the recipe was worked out once.⁵⁶⁷⁹¹⁰

A closer look

Splitting a pot into a number of servings assumes every serving is the same size, and the cooked weight of a dish isn't fixed even when the recipe is. In USDA's cooking yield study, medium fat ground beef browned as crumbles averaged 67 percent of its raw weight, but individual samples ranged from 64 to 72 percent. Moisture loss was 27.8 percent of the raw weight and fat loss 5.3 percent, so most of the missing weight was water. Weighing the finished pot each time you cook it picks up that difference, and dividing by a fixed serving count doesn't.¹

Questions and answers

Should I use raw or cooked numbers for the ingredients?

Raw, to match the raw weights you put in the pot. The cooked weight comes in once, for the whole dish. Pairing raw beef weight with the cooked crumbles entry would count 256 calories per 100 grams instead of 215, 41 too many.⁷⁸

How do I count calories in a recipe without a scale?

Add up the ingredients from package weights and labels, then split the finished dish into equal containers when you put it away. Each container is the total divided by the number of containers. For a single plate you didn't portion yourself, estimate it by eye the way the portion control guide describes.

Why not just divide by the number of servings?

That works when every serving really is the same size. Weighing the cooked dish lets you log whatever you actually served, a big bowl one night and a small one the next, from the same pot.

Does cooking change vitamins the way it changes weight?

Some vitamins are lost in cooking, which is why USDA keeps a retention table. Its own example puts boiled spinach at 85 percent of raw spinach's vitamin C, 23.8 milligrams per 100 grams against 28.²

Put your recipe in once

Log calories by hand for free, and the number you worked out goes straight in. With Pro, paste or describe a recipe and TrueCal estimates per-serving nutrition, and you can save meals to reuse.

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Sources

USDA Table of Cooking Yields for Meat and Poultry. Showell, Williams, Duvall, Howe, Patterson, Roseland, Holden. 2012.
USDA Table of Nutrient Retention Factors, Release 6. U.S. Department of Agriculture, Agricultural Research Service. 2007.
International Journal of Food Sciences and Nutrition. Fillion, Henry. 1998.
USDA FoodData Central. U.S. Department of Agriculture. 2026.
USDA FoodData Central, Oil, olive, salad or cooking. U.S. Department of Agriculture. 2019.
USDA FoodData Central, Onions, raw. U.S. Department of Agriculture. 2019.
USDA FoodData Central, Beef, ground, 85 percent lean meat, 15 percent fat, raw. U.S. Department of Agriculture. 2019.
USDA FoodData Central, Beef, ground, 85 percent lean meat, 15 percent fat, crumbles, cooked, pan-browned. U.S. Department of Agriculture. 2019.
USDA FoodData Central, Tomatoes, red, ripe, canned, packed in tomato juice. U.S. Department of Agriculture. 2019.
USDA FoodData Central, Beans, kidney, red, mature seeds, canned, drained solids. U.S. Department of Agriculture. 2019.