Table of Fuel Calorific Values

Table of Fuel Calorific Values (kcal/kg and MJ/kg)

Calorific value is the amount of energy released when a fuel is completely combusted and is generally measured in kcal/kg or MJ/kg. For solid fuels, the value typically ranges from approximately 2,000–8,000 kcal/kg; for liquid fuels, from 9,500–10,500 kcal/kg; and for gaseous fuels, from 8,000 kcal/m³ to 12,000 kcal/kg. The table below allows you to compare the heating values of the most commonly used fuels at a glance.

Short answer: Among commonly used fuels, hydrogen has the highest calorific value, followed by LPG/propane and diesel fuel. Among solid fuels, anthracite has the highest heating value, while untreated wood has the lowest.

Fuel Calorific Value Comparison Table

The values below are approximate ranges based on the lower heating value (net calorific value). Actual values may vary depending on moisture content, ash content, source, and sample type.

Solid Fuels

Fuel	Calorific Value (kcal/kg)	Calorific Value (MJ/kg)
Anthracite	7,000 – 8,000	29 – 34
Imported Hard Coal	6,000 – 7,500	25 – 31
Coke	6,500 – 7,200	27 – 30
High-Quality Lignite	4,000 – 5,000	17 – 21
Lignite (Türkiye, Low Grade)	1,500 – 3,500	6 – 15
Wood Pellets (ENplus A1)	4,000 – 4,800	17 – 20
Hazelnut Shells	4,000 – 4,800	17 – 20
Olive Pomace / Olive Pits	3,500 – 4,500	15 – 19
RDF / SRF (Refuse-Derived Fuel)	3,000 – 5,000	12 – 21
Firewood (Dry, ~20% Moisture)	2,800 – 3,500	12 – 15

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Liquid Fuels

Fuel	Calorific Value (kcal/kg)	Calorific Value (MJ/kg)
Gasoline	10,400 – 10,600	43 – 44
Diesel Fuel	10,000 – 10,300	42 – 43
Heating Oil	9,700 – 10,200	41 – 43
Fuel Oil	9,600 – 10,000	40 – 42

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Gaseous Fuels and Other Sources

Source	Calorific Value	MJ Equivalent
Hydrogen	~28,700 kcal/kg	~120 MJ/kg
Propane	11,000 – 12,000 kcal/kg	46 – 50 MJ/kg
LPG (Mixture)	11,000 – 11,900 kcal/kg	46 – 50 MJ/kg
Natural Gas (Lower Heating Value)	~8,250 kcal/m³	~34.5 MJ/m³
Natural Gas (Higher Heating Value)	~9,150 kcal/m³	~38.3 MJ/m³
Electricity	860 kcal/kWh	3.6 MJ/kWh

Note: The values in the table are intended as general reference values. The actual calorific value of a fuel can only be accurately determined in a laboratory using a bomb calorimeter, in accordance with the relevant standards such as ISO 1928 and ASTM D5865.

What Is Calorific Value?

Calorific value, also known as heating value, is the amount of heat energy released when a unit mass or volume of fuel is completely combusted. From the energy sector and cement production to food analysis and feed formulation, it is a key parameter used to determine fuel quality, efficiency, and cost. A fuel with a higher calorific value generally provides the same amount of energy with less mass, making it more economical and efficient.

In Türkiye, kcal/kg (kilocalories per kilogram) is the most commonly used unit, while international standards generally use MJ/kg (megajoules per kilogram). For gaseous fuels, the unit is usually expressed on a volumetric basis, such as kcal/m³.

Difference Between Lower Heating Value and Higher Heating Value

Calorific value can be expressed in two different ways, and understanding this distinction is essential for interpreting the values in the table correctly:

Higher Heating Value (HHV – Gross Calorific Value): The total amount of energy calculated by including the latent heat released when the water vapor produced during combustion condenses. A bomb calorimeter directly measures this value.

Lower Heating Value (LHV – Net Calorific Value): The practically usable energy obtained after subtracting the heat of condensation of the water vapor discharged into the atmosphere with the flue gases. This value is generally used in boiler and furnace efficiency calculations.

The difference between these two values depends on the hydrogen and moisture content of the fuel. As moisture content increases, the lower heating value decreases significantly. For this reason, the “as-received” and “dry basis” analysis results of the same coal sample may differ.

How to Convert kcal/kg to MJ/kg

The following practical conversion factors can be used:

1 MJ/kg = 238.85 kcal/kg (approximately 239)
1 kcal/kg = 0.004187 MJ/kg
1 kWh = 860 kcal = 3.6 MJ

Example: A wood pellet with a heating value of 18 MJ/kg corresponds to approximately:

18 × 239 = 4,300 kcal/kg

Factors Affecting Calorific Value

Four main factors explain why the calorific value of the same type of fuel is usually given as a range.

Moisture content directly reduces the usable heat because energy is consumed to evaporate the water contained in the fuel.

Ash and inorganic matter content reduce the calorific value by increasing the proportion of non-combustible material.

The source and type of fuel, such as the geological age of lignite or the origin of a coal reserve, naturally determine its energy content.

Finally, sample preparation and homogeneity affect the repeatability of laboratory results. A poorly prepared sample may produce results that do not accurately represent the actual calorific value of the material.

How Is Calorific Value Measured?

The values provided in tables are average reference values. However, for commercial, regulatory, or process-related applications, the exact calorific value of the actual sample must be determined.

This measurement is performed using a bomb calorimeter. The sample is ignited under high-pressure oxygen inside a sealed steel vessel known as a bomb. The calorific value is then calculated by precisely measuring the temperature increase in the surrounding water caused by the heat released during combustion. Measurements are performed in accordance with international standards such as ISO 1928 and ASTM D5865.

Measurement accuracy, repeatability, and compliance with international standards are essential for obtaining reliable results from a wide variety of samples, including coal, biomass, RDF, liquid fuels, food, and animal feed.

Debye Technic IC Series bomb calorimeters, designed and manufactured entirely in Türkiye, have been developed to determine the calorific value of these samples with high accuracy and full compliance with relevant standards.

Frequently Asked Questions

Which fuel has the highest calorific value?
Among commonly used fuels, hydrogen has the highest calorific value at approximately 28,700 kcal/kg. It is followed by LPG/propane at approximately 11,000–12,000 kcal/kg and liquid fuels such as diesel and gasoline at approximately 10,000–10,600 kcal/kg. Among solid fuels, anthracite has the highest value at approximately 7,000–8,000 kcal/kg.

What is the calorific value of coal in kcal/kg?
It varies depending on the type of coal. Anthracite generally ranges from 7,000–8,000 kcal/kg, imported hard coal from 6,000–7,500 kcal/kg, high-quality lignite from 4,000–5,000 kcal/kg, and lower-grade lignites found in Türkiye from approximately 1,500–3,500 kcal/kg.

What is the calorific value of wood pellets?
The calorific value of ENplus A1 quality wood pellets is approximately 4,000–4,800 kcal/kg (17–20 MJ/kg). The value increases as moisture content decreases.

What is the calorific value of natural gas?
The lower heating value of natural gas is approximately 8,250 kcal/m³, while its higher heating value is approximately 9,150 kcal/m³.

How many kcal/kg is 1 MJ/kg?
1 MJ/kg = 238.85 kcal/kg, or approximately 239 kcal/kg.

What is the difference between lower heating value and higher heating value?
The Higher Heating Value (HHV) includes the heat recovered from the condensation of water vapor produced during combustion. The Lower Heating Value (LHV) excludes this heat and represents the energy that is practically available for use. The difference between the two depends primarily on the moisture and hydrogen content of the fuel.

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