Calorie Density Calculator
Find calories per gram and per 100 g from the calories and weight of your food. Add a portion weight to estimate its calories.
Your result will appear here.
How to calculate calorie density
- Find the calories for the amount of food you weighed, using its label or a matching nutrition entry.
- Enter the energy value and choose kcal or kJ to match the label. Enter the food weight in grams or weight ounces.
- Calculate to see calories per gram and per 100 g. Add a portion weight if you also want its estimated calories.
Calorie density = total calories ÷ food weight in grams
Portion calories = calorie density × portion weight in grams
A worked example
Suppose a 150 g portion contains 300 kcal. Its calorie density is 300 ÷ 150 = 2 kcal/g, or 200 kcal per 100 g. An evenly mixed 75 g share would contain 150 kcal. The same 300 kcal can be entered as 1,255.2 kJ by selecting kJ. It gives the same result. These numbers illustrate the calculation; they are not a nutrition reference for a particular food.
Match the calories to the weight
If you enter calories per serving, use that serving’s weight. If you enter calories for a whole batch, weigh the finished batch without its container. Do not combine dry-food calories with a cooked-food weight unless the calories describe that whole cooked batch.
Water gained or lost during cooking changes calories per gram. Discarded oil, cooking liquid or food can also change the calories left in the batch. For a mixed dish, a weighed portion only represents the batch when ingredients are distributed evenly.
What the result can tell you
Calorie density describes how much energy a food provides for its weight. It does not measure overall nutrition or predict how full you will feel. Nuts and oils, for example, can have a high calorie density and still fit a balanced diet. Compare similar foods alongside their nutrients, ingredients and the amount you actually eat.
Common questions
Does this calculator find calories for me?
No. Enter calories from a label or a suitable food entry. Use our Recipe Nutrition Calculator to estimate calories for a dish from its ingredients.
Are calories and kcal the same here?
Food Calories mean kilocalories, shown as kcal. If your label gives kilojoules, select kJ. The tool divides kJ by 4.184 before calculating calorie density; do not add kcal and kJ together. A weight ounce is not a fluid ounce.
Why does my portion estimate differ from the label?
Food composition, serving weights and label rounding can differ. Check that both calorie and weight values describe the same food and amount.
Calculations run in your browser tab. This tool does not save your entries. Print a result to keep it. See our Privacy Policy for the website’s wider data practices.
Method and references
We convert entered kilojoules to kcal when needed (1 kcal = 4.184 kJ), then divide kcal by the weight converted to grams. One weight ounce is 28.349523125 g. Calculations keep unrounded values internally; displayed results are rounded.