Food Energy Density Calculator
The energy density of a food from its label — calories per gram — with the low / medium / high band it falls in and the energy in your serving.
Energy density is how many calories a food packs per gram.
How the food energy density calculator works
Energy density is how many calories a food packs per gram. Foods high in water and fibre (vegetables, fruit, soups) sit under 1.5 kcal/g; most cooked meals 1.5–4; nuts, oils, chocolate and crisps above 4. Because people tend to eat a fairly constant weight of food, choosing lower-density foods is one of the best-supported ways to eat fewer calories without feeling hungrier.
Formula: energy density = kcal per 100 g ÷ 100
Worked examples
| Inputs | Energy density | Note |
|---|---|---|
| 380 kcal per 100 g, 45 g serving | 3.8 kcal/g | 3.8 kcal/g — medium; 171 kcal |
| 1,600 kJ per 100 g | 3.82 kcal/g | 3.82 kcal/g |
| Broccoli, 34 kcal per 100 g | 0.34 kcal/g | 0.34 kcal/g — very low |
FAQFrequently asked questions
Why does energy density matter more than calories per serving?
Serving sizes on packs are chosen by manufacturers; grams are what you actually eat. Two foods at 200 kcal a serving can differ tenfold in how much food that is, and the bulkier one fills you up more.
What is a low-energy-density diet?
One built on foods under about 1.5 kcal/g — vegetables, fruit, soups, wholegrains, lean protein — with high-density foods in small amounts. Trials show people eat fewer calories on it without reporting more hunger.
Is high energy density bad?
Not in itself: nuts, olive oil and oily fish are dense and healthy. It means portions need to be smaller for the same calories, and that they are easy to over-eat.
How do I convert kJ to kcal?
Divide by 4.184. Australian and some European labels use kilojoules; the calculator accepts either.
Where these figures come from
- US FDA — Safe Minimum Internal Temperatures — the internal temperatures the roasting calculator targets
- NIST SP 811 — Guide for the Use of the International System of Units — the exact weight and volume conversions used throughout
- UK Food Standards Agency — food safety and labelling standards
Last checked: September 2026. Baking ratios follow standard baker's percentage practice; roasting guidance follows published safe internal temperatures.