Quick answer
Calorie density = calories ÷ grams. 250 kcal in 100 g is 2.5 kcal per gram, or 250 kcal per 100 g.
Enter the calories and the weight of the food. The calculator returns kcal per gram and per 100 g.
Related tools: Calorie Calculator: Daily calories to maintain, lose or gain weight. BMR Calculator: Estimate basal metabolic rate with the Mifflin–St Jeor and revised Harris–Benedict equations. TDEE Calculator: Total daily energy expenditure from BMR and activity level.
How to use the Calorie Density Calculator
- Enter calories (kcal) (0 or more).
- Enter weight (g) (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Calories | A number, in kcal | ≥ 0 |
| Weight (g) | A number | > 0 |
Formula and method
Formula
calorie density = calories ÷ grams
IEEE-754 double precision; shown to the decimals indicated.
Shown per gram and per 100 g. Informational estimate, not medical advice. Talk to a qualified health professional about your own situation.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Calories = 250; Weight (g) = 100.
| Result | Value |
|---|---|
| Calorie density | 2.5 kcal/g |
| Per 100 g | 250 kcal |
Example 2
Inputs: Calories = 89; Weight (g) = 30.
| Result | Value |
|---|---|
| Calorie density | 2.97 kcal/g |
| Per 100 g | 296.7 kcal |
Example 3
Inputs: Calories = 520; Weight (g) = 80.
| Result | Value |
|---|---|
| Calorie density | 6.5 kcal/g |
| Per 100 g | 650 kcal |
The first line is the headline result (calorie density). Below it the calorie Density Calculator lists per 100 g, which describe the same case from other angles. IEEE-754 double precision; shown to the decimals indicated.
Why density matters
Foods high in water and fibre, such as vegetables and fruit, have low densities (0.2 to 0.8 kcal/g), while oils are about 9 kcal/g. Choosing lower-density foods lets you eat larger volumes for the same calories.
Weigh as eaten
Weigh the food as eaten: cooked rice has fewer calories per gram than dry rice because of water. Compare labels using per-100 g values.
How the result changes with calories
Holding every other input at the first worked example, this table changes only calories. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Calories | Calorie density | Per 100 g |
|---|---|---|
| 125 | 1.25 kcal/g | 125 kcal |
| 250 | 2.5 kcal/g | 250 kcal |
| 500 | 5 kcal/g | 500 kcal |
| 1000 | 10 kcal/g | 1,000 kcal |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Weight (g): entering "0" shows "Weight (g) must be greater than 0." beside that field and no result.
- Calories: entering "-1" shows "Calories must be at least 0." beside that field and no result.
Choosing between the Calorie Density Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Calorie Calculator](/health/calorie-calculator/) | units, sex and weight | Maintenance calories |
| [BMR Calculator](/health/bmr-calculator/) | units, sex and weight | Basal metabolic rate |
| [TDEE Calculator](/health/tdee-calculator/) | units, sex and weight | Total daily energy expenditure |
| [Protein Calculator](/health/protein-calculator/) | units, body weight and profile | Protein per day |
| [Macro Calculator](/health/macro-calculator/) | daily calories, carbohydrate and protein | Carbohydrate |
Background: nutrition estimates
Nutrition calculators estimate: they use population-average equations and food tables, and different tables give different numbers for the same food. Certain medical conditions change energy needs in ways basic formulas cannot see, and only laboratory analysis gives exact nutrient values.
Use the result as a starting point, track what actually happens over a few weeks and adjust; ask a qualified professional about medical or clinical decisions.
Assumptions and limitations
- Weigh the food as eaten
- Not a diagnosis
This calculator gives general information based on published formulas. It is not medical advice, and it cannot account for your health history. Talk to a qualified clinician about decisions that affect your health.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for weight (g) and calories to confirm this.
Frequently asked questions
What is a low calorie density?
Under about 1.5 kcal/g.
How dense is fat?
Fat has about 9 kcal/g, more than twice protein or carbohydrate at about 4 kcal/g.
Does cooking change density?
Yes, through water gain or loss.
What does the Calorie Density Calculator calculate?
Calories per gram of a food. It returns Calorie density and Per 100 g.
What formula does the Calorie Density Calculator use?
calorie density = calories ÷ grams. Shown per gram and per 100 g.
What do I need to enter in the calorie Density Calculator?
You enter Calories (kcal) and Weight (g).
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Weigh the food as eaten.
What are the limits of this calculator?
Weigh the food as eaten. Not a diagnosis.
What is an example of a calorie Density result?
With calories 250 and weight (g) 100, the calorie density is 2.5 kcal/g.
Can I rely on this calculator for a decision?
This calculator gives general information based on published formulas. It is not medical advice, and it cannot account for your health history. Talk to a qualified clinician about decisions that affect your health. For this calculator in particular: Weigh the food as eaten.
Related calculators
- Calorie Calculator — Daily calories to maintain, lose or gain weight.
- BMR Calculator — Estimate basal metabolic rate with the Mifflin–St Jeor and revised Harris–Benedict equations.
- TDEE Calculator — Total daily energy expenditure from BMR and activity level.
- Protein Calculator — Daily protein target by body weight and activity.
- Macro Calculator — Split daily calories into grams of carbohydrate, protein and fat.
- Calories Burned Calculator — Estimate calories burned from activity, body weight and time using MET values.
- Fiber Calculator — Daily fiber target from calorie intake.
- Net Carb Calculator — Net carbohydrates after subtracting fiber and sugar alcohols.
Sources
- Common definition used on this page. No single authoritative standard defines it, so the exact formula is stated in the formula section above
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.