Calculate grams from kilojoules and energy density, or find energy and kJ per gram from mass with support for nutrition label units.

A known energy density is required. Food presets are approximate nutrient factors, not the composition of a whole food.

kJ to Grams Formula

The following formula is used to calculate the grams for a given amount of kilojoules and energy per gram.

g = (Kj) / (E)

Variables:

  • g is the grams
  • Kj is the kilojoules
  • E is the energy per gram in kilojoules per gram

To calculate the grams, divide the kilojoules by the energy per gram.

Kilojoules to Grams Conversion Table (Assumes energy density = 17 kJ/g)
Kilojoules (kJ) Grams (g)
100.588
201.176
301.764
502.941
754.412
1005.882
1207.059
1508.824
20011.765
25014.706
30017.647
35020.588
40023.529
50029.412
60035.294
75044.118
100058.824
150088.235
2000117.647
2500147.059
*Assumes energy per gram = 17.00 kJ/g (typical for carbohydrate/protein). Formula: grams = kilojoules ÷ (kJ/g).

What is kJ to Grams?

kJ to grams is a conversion that allows you to determine the mass of a substance based on its energy content and the energy per gram. For a food, use its labeled or otherwise known energy density. Nutrient presets are approximate; a whole food need not have the energy density of one pure nutrient. There is no universal kJ-to-grams factor.

How to Calculate kJ to Grams?

The following steps outline how to calculate kJ to grams.

  1. First, determine the kilojoules (Kj).
  2. Next, determine the energy per gram (E).
  3. Finally, calculate the grams using the formula g = Kj / E.
  4. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Kilojoules (Kj) = 500

Energy per gram (E) = 2.5 kJ/g