Skip to content
ENExplore Calculators

Heat Of Combustion Calculator

Work out heat of combustion instantly with clear inputs, formula shown and shareable results.

About Heat Of Combustion Calculator

Enthalpy of combustion is quoted per mole, so a mass of fuel must first be converted to moles before the heat release can be found. Burning 12 g of propane (44.1 g/mol, -2220 kJ/mol) releases about 604 kJ. Dividing the molar value by the molar mass gives the specific energy, which is the figure that matters when fuels are compared by mass.

Formulas

Heat released

Q = (mass / molar mass) x |dHc|

Specific energy

kJ/g = |dHc| / molar mass

Worked example

With the default values below, Heat Of Combustion Calculator returns Energy Released of 604.08. Change any input above and every figure here is recalculated in your browser.

Inputs used

Mass of fuel burnedminimum 0 g
12 g
Molar mass of the fuelminimum 0 g/mol
44.1 g/mol
Molar enthalpy of combustion
-2,220 kJ/mol

Results

Energy Released
604.08 kJ
Moles Burned
0.27211
Specific Energy
50.340 kJ/g
Specific Energy Per Kilogram
50,340.1 kJ/kg

Step by step

  1. 1Values used
  2. 2Heat released
  3. 3Specific energy
  4. 4Energy Released= 604.08 kJ
  5. 5Moles Burned= 0.27211
  6. 6Specific Energy= 50.340 kJ/g
  7. 7Specific Energy Per Kilogram= 50,340.1 kJ/kg

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is the released energy shown as positive?

The enthalpy change is negative because the system loses energy; the heat delivered to the surroundings is the same magnitude, stated positively.

Is this the higher or lower heating value?

Whichever your molar enthalpy refers to. Standard combustion enthalpies assume liquid water products, which corresponds to the higher heating value.

Related Calculators

Heat Of Combustion Calculator | Calcrivo