Weigh your food in the same state as the database entry you log. If the entry says raw, weigh it raw. If it says cooked, weigh it cooked. The number on the scale and the number in the entry have to describe the same thing, or the error can be large.
| Food (USDA entry) | State | kcal per 100 g | Protein per 100 g |
|---|---|---|---|
| Chicken breast, skinless, boneless (171077) | Raw | 120 | 22.5 g |
| Chicken breast, meat only (171477) | Roasted | 165 | 31 g |
| White long-grain rice (168877) | Raw | 365 | 7.13 g |
| White long-grain rice (168878) | Cooked | 130 | 2.69 g |
| Oats, regular and quick (173904) | Dry | 379 | 13.2 g |
Source: USDA FoodData Central, SR Legacy entries, values per 100 g as shown on each entry’s page.
Why one food has two calorie numbers
Cooking changes the weight of food far more than it changes the calories in it. Chicken loses water as it cooks, so a piece of it weighs less afterward. Rice and oats do the opposite: they soak up water and end up much heavier.
Calories per 100 g are a ratio, calories divided by weight. When the weight changes and the calories mostly stay put, the ratio moves. Roasted chicken is 165 kcal per 100 g against 120 for raw, because the same food is packed into fewer grams. Cooked rice is 130 kcal per 100 g against 365 for raw, because water has spread the same grains across more grams.
That is why two entries for the same food can both be right. They answer different questions: how much energy is in 100 g of this, in this state.
What USDA lists for chicken, rice and oats
The table above uses USDA FoodData Central, the government database behind many food apps. All five entries come from its SR Legacy data set. The entry names matter, so here they are in full:
- 171077: “Chicken, broiler or fryers, breast, skinless, boneless, meat only, raw”
- 171477: “Chicken, broilers or fryers, breast, meat only, cooked, roasted”
- 168877: “Rice, white, long-grain, regular, raw, enriched”
- 168878: “Rice, white, long-grain, regular, enriched, cooked”
- 173904: “Cereals, oats, regular and quick, not fortified, dry”
The two chicken entries are not a matched pair from one experiment. They are separate USDA samples, with slightly different descriptions: one says skinless and boneless, the other says meat only. Treat any comparison between them as a good approximation, not a measurement of what happens in your own oven.
For oats we list only the dry entry. The cooked figure depends heavily on how much water goes into the pot, which is a reason to weigh oats dry when you can.
How to convert between states
If you weighed one state and only have the entry for the other, you can convert. The method has two steps.
- Divide the calories per 100 g of the raw entry by the calories per 100 g of the cooked entry. This gives a ratio that says how the weight changes.
- Multiply your weight by that ratio to estimate the weight in the other state.
The assumption behind this is that cooking leaves the total calories in the food unchanged, so any change in calories per 100 g comes from the weight change alone. That is an approximation. Fat drips out of some cuts, oil gets absorbed by others, and the two USDA entries come from different samples. The results below are our arithmetic on USDA values. They are not a measured cooking yield, and your own kitchen will differ.
Here is the ratio for each food:
| Food | Working | Result |
|---|---|---|
| Chicken breast | 120 / 165 = 0.73 | 100 g raw becomes about 73 g roasted |
| White rice | 365 / 130 = 2.81 | 100 g dry becomes about 281 g cooked |
You can check the chicken figure on protein instead: 22.5 / 31 = 0.73. It agrees. For rice, protein gives 7.13 / 2.69 = 2.65, a little lower, which shows how much these ratios move depending on which nutrient you use.
Worked example: chicken breast
Say you buy a 200 g raw breast. Using the raw entry (171077), it holds 200 x 1.20 = 240 kcal and 200 x 0.225 = 45 g of protein.
After cooking, our ratio suggests it weighs about 200 x 0.73 = 146 g. Log that finished piece against the roasted entry (171477) and you get 146 x 1.65 = 241 kcal and 146 x 0.31 = 45 g of protein. The two routes land within a calorie of each other, which is what you would expect, since we built the ratio from the same numbers.
The mistakes are where it gets interesting:
- Weigh the finished 146 g, log it with the raw entry: 146 x 1.20 = 175 kcal and 33 g of protein. That undercounts by about 65 kcal and 12 g of protein.
- Weigh the raw 200 g, log it with the roasted entry: 200 x 1.65 = 330 kcal and 62 g of protein. That overcounts by about 90 kcal and 17 g of protein.
Neither slip looks dramatic on a single meal. Repeated across a week of lunches, the gap adds up.
The weight loss in cooking is not a fixed number either. Our two USDA entries imply a loss of roughly 27 percent, older pages on this site say roughly a quarter, and the real figure moves with the cut, its thickness, the method and how long it cooks. Use the ratio as a starting estimate. If you cook the same chicken often, weigh a piece before and after once, and use your own ratio.
Worked example: rice and oats
Rice is where mixing states costs the most, because the two entries are so far apart.
Say you cook a batch and serve 150 g of the finished rice.
- Logged correctly against the cooked entry (168878): 150 x 1.30 = 195 kcal.
- Logged against the raw entry (168877) by mistake: 150 x 3.65 = 548 kcal.
That is an overcount of over 350 kcal from one wrong dropdown choice.
The reverse also happens. Say you weigh 60 g of dry rice before boiling it, then log it against the cooked entry: 60 x 1.30 = 78 kcal, when the dry entry gives 60 x 3.65 = 219 kcal. Here the tracker undercounts by 141 kcal.
Oats follow the same logic. The USDA dry entry (173904) lists 379 kcal and 13.2 g of protein per 100 g. A 40 g scoop of dry oats is 40 x 3.79 = 152 kcal and about 5.3 g of protein. Once the oats are cooked, weighing the bowl and logging it as dry oats would count the water as if it were food. Weigh the oats dry, before the water goes in, and log the dry entry. If you would rather weigh the finished bowl, look for a cooked oats entry and check that it says how it was prepared.
For a sense of how much heavier rice gets, our ratio says 100 g dry becomes about 280 g cooked. That amount of water is the reason a cup of cooked rice looks like so much more food than it is.
Where the numbers come from on Calorilator’s food pages
The food pages on this site use USDA entries, and each page shows one state. It helps to know which before you compare.
- Chicken breast lists the raw skinless boneless cut, the same entry as 171077 above. That is how USDA lists it, and the page says so. If you weigh finished chicken, use the roasted figure in this article or convert with the ratio.
- White rice shows the cooked entry, 168878.
- Oats shows the dry entry, 173904.
Other foods follow their own USDA entry. Quinoa, pasta and beans, for instance, are usually listed cooked, so check the label on each food page in the food index before you weigh. The name at the top of the page tells you the state, and the serving label repeats it.
Common mistakes
Mixing states. The classic slip is the one above: weighing cooked food, then picking the first search result, which happens to be a raw or dry entry. Read the entry’s full name, not just the first word.
Forgetting what went into the pan. Oil, butter and sauce add calories that neither the raw nor the cooked entry includes. Weigh them separately or log them as their own line. The calorie count accuracy article covers why cooking fats are one of the easiest things to miss.
Using a generic entry. “Chicken” can mean breast, thigh or a whole bird, with or without skin. The USDA entry called “meat only, raw” for chicken in general is a different food from the skinless breast. When an entry is vague, pick a more specific one.
Ignoring bone and skin. A bone-in or skin-on piece weighs more than the meat inside it. The entries above are boneless, so trim first or use an entry that matches what you weigh.
Switching states halfway through a week. Some people log one meal raw and the next cooked, with entries that match each time. That works, but only if the entries do match. It is easy to lose track, so it is worth choosing one habit for each food and keeping to it.
A workable routine
The most consistent habit is to weigh raw, before cooking, whenever you can. Raw weight does not change with how long something spent in the pan, and the raw entries are easy to find.
When you batch cook, the routine looks like this:
- Weigh the raw food and note the total.
- Cook it, then weigh the finished batch.
- Divide the finished batch into portions, weighing each one.
- Work out each portion’s calories as the total raw calories multiplied by the portion’s weight, divided by the weight of the whole finished batch.
If you did not weigh raw, weigh the finished batch and use the cooked entry instead. For meal prep, the raw total shared out by portion weight avoids depending on a cooked entry at all, which helps when the entry you would pick is vague. The high-protein meal prep guide covers portioning cooked protein, and how long meal-prepped food lasts covers storing cooked rice and other batch foods.
Once your portions are logged correctly, the macro calculator can turn them into protein, carbohydrate and fat against a target. Chicken and other protein-heavy foods are worth checking against the protein calculator too.
What this article does not cover
These are general points about matching states, not personal advice. If you have a medical condition or are following a plan from a clinician or dietitian, ask them how to measure and log your food. Cooking methods, safe temperatures and storage times are outside this article. The figures above are USDA reference values, and packaged or restaurant food will differ.
Sources
All figures in the tables come from the USDA FoodData Central entries cited in the sources list. Ratios, converted weights and the calorie totals in the worked examples are Calorilator’s own arithmetic on those values, with the assumptions stated above.