Heat moves by conduction through solids, convection by moving fluids and radiation by electromagnetic waves. Insulation, radiators, cooking and climate all depend on balancing these three.
How to use the Heat Transfer Calculator
- Mode
- Mass m
- Specific heat c
- Wall material
- Thermal conductivity k
- Thickness d
- Heat transfer coefficient h
- Emissivity ε
- Area A
- Temperature 1 (hot)
- Temperature 2 (cold)
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Choose the mode and enter the values.
Tips
- Use absolute temperature (K) in gas laws and efficiency formulas.
- Temperature differences are the same in K and °C.
- Heat = mass × specific heat × temperature change when no phase change occurs.
- Phase changes need latent heat at a constant temperature.
Common mistakes to avoid
- Using °C in pV = nRT.
- Forgetting latent heat during melting or boiling.
- Confusing heat capacity (J/K) with specific heat (J/(kg·K)).
Inputs explained
| Field | What to enter |
|---|---|
| Mode | Choose one: Temperature change of a mass, Conduction, Convection, Radiation |
| Mass m | Units: kg, g, mg, t, lb, oz |
| Specific heat c | Units: J/(kg·K), kJ/(kg·K), J/(g·K), BTU/(lb·°F), cal/(g·°C) |
| Wall material | Choose one: Copper, Aluminium, Carbon steel, Stainless steel … |
| Thermal conductivity k | Units: W/(m·K), BTU/(h·ft·°F) |
| Thickness d | Units: cm, mm, m, in, ft |
| Heat transfer coefficient h | Units: W/(m²·K), BTU/(h·ft²·°F) |
| Emissivity ε | A number |
| Area A | Units: m², cm², mm², km², in², ft² |
| Temperature 1 (hot) | Units: °C, °F, K |
| Temperature 2 (cold) | Units: °C, °F, K |
Example values
How the main result changes when Mass m changes and everything else stays at the example values above:
| Mass m (kg) | Heat transferred (J) |
|---|---|
| 0.5 | 41,820 |
| 0.75 | 62,730 |
| 1 | 83,640 |
| 1.25 | 104,550 |
| 1.5 | 125,460 |
| 2 | 167,280 |
Formula
Q = m·c·ΔT · Conduction: q = k·A·ΔT/d · Convection: q = h·A·ΔT · Radiation: q = ε·σ·A·(T₁⁴ − T₂⁴)Worked example
Inputs — Mode: Conduction; Wall material: Brick; Thickness d: 20 cm; Area A: 10 m²; Temperature 1 (hot): 20 °C; Temperature 2 (cold): 0 °C.
Results — Heat transfer rate = 720 W.
Key terms
- Thermal conductivity
- Heat flow per metre per kelvin.
Frequently asked questions
What are the three modes of heat transfer?
Conduction, convection and radiation.
Why does radiation use T⁴?
Emitted power grows with the fourth power of absolute temperature.
What is a typical h for still air?
About 5–25 W/(m²·K).
How do I reduce conduction losses?
Use thicker material with lower conductivity.
What formula does the Heat Transfer Calculator use?
Q = m·c·ΔT · Conduction: q = k·A·ΔT/d · Convection: q = h·A·ΔT · Radiation: q = ε·σ·A·(T₁⁴ − T₂⁴).