Heat of Combustion Calculator

Heat (q) Calculator

Compute heat change using q = m · c · ΔT (sensible heat).

2026-05-06T10:07:27.222Z
g
J/g·°C
°C

Heat Energy (q)

4184.00 J

4.1840 kJ · 1.0000 kcal · 3.966 BTU

Mass:
100.000 g
0.1000 kg · 0.2205 lb
Specific Heat:
4.1840 J/g·°C
4184.00 J/kg·°C

Formula: q = m · c · ΔT

About This Calculation

This tool calculates sensible heat change using the classical thermodynamic relation q = m · c · ΔT. It assumes uniform temperature change across the mass and uses the specific heat capacity provided. Specific heat varies with material and temperature; the default value shown is for liquid water at typical temperatures. For combustion energy (higher-order energetic content), use tabulated heats of combustion per mass of the fuel.

Use results to estimate energy transfer for heating or cooling processes, calorimetry checks, and simple engineering approximations. Remember that real systems may have heat losses, non-uniform temperature distributions, and phase changes which are not included here.

How to Use

  1. Enter mass in grams (g). Convert units externally if needed.
  2. Enter the specific heat capacity in J/g·°C (common reference values available in tables).
  3. Enter the temperature difference in °C (ΔT = Tfinal − Tinitial).
  4. Read the computed heat in J, kJ, kcal and BTU; verify mass and units.
  5. Apply corrections for phase changes, reaction enthalpies, or system losses as required.

Worked Example

Given: m = 200 g, c = 4.184 J/g·°C, ΔT = 25 °C
Step: q = 200 · 4.184 · 25 = 20920.00 J
Result: 20920.00 J (20.9200 kJ)

Frequently Asked Questions

What formula is used?

q = m · c · ΔT where m is mass, c is specific heat, and ΔT is temperature change.

What units are shown?

Outputs include J, kJ, kcal, and BTU; mass shown in g, kg, and lb.

Why convert to kcal?

kcal is commonly used in chemistry and food energy contexts for human-readable energy values.

What if mass is zero?

Heat is zero if mass or ΔT is zero; negative or zero mass is invalid for this tool.

Can I use kg directly?

Enter mass in grams; use the kg output for confirmation (mass in kg = g ÷ 1000).

How precise are conversions?

Conversions use standard factors (1 kJ = 1000 J, 1 kcal = 4184 J, 1 BTU ≈ 1055.06 J).

Is this combustion heat?

This computes sensible heat change (q). Heat of combustion is typically reported per mass on a different basis — consult material tables for true heat of combustion.

Any safety notes?

Handle energetic materials with care; use appropriate safety and regulatory guidance when interpreting energy numbers.

Formula: q = m · c · ΔT — mass in g, c in J/g·°C, ΔT in °C. Conversions assume standard factors.

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