Heat Transfer Calculator
Heat transfer by conduction through a material follows Q = mcΔT. This calculator computes the heat energy (in Joules and calories) absorbed or released when a known mass of material changes temperature.
Advertisement
Calculator
See your Heat Transfer Calculator results
Enter your email to unlock results — free forever.
No spam, ever. Unsubscribe at any time.
Advertisement
Formula
Q = mcΔT
Heat transferred Q equals mass (m) times specific heat capacity (c) times temperature change (ΔT). Specific heat of water: 4,186 J/(kg·°C). Specific heat of air: 1,005 J/(kg·°C). Aluminum: 900. Steel: 490. Copper: 385. 1 calorie = 4.184 J. 1 food Calorie = 4,184 J = 1 kcal.
How to use the Heat Transfer Calculator
- 1
Enter your mass
Value should be in kg.
- 2
Enter your specific heat capacity
Value should be in J/(kg·°C).
- 3
Enter your temperature change (δt)
Value should be in °C.
- 4
Read your results instantly
Results update in real time as you type.
Advertisement
Specific heat capacity
Specific heat capacity (c) is the energy needed to raise 1 kg of a substance by 1°C. Water has one of the highest specific heats: 4,186 J/(kg·°C). This means water requires a lot of energy to heat up and releases a lot when it cools — which is why oceans moderate coastal climates, why water is used as engine coolant, and why a cup of hot tea stays warm.
Metals have much lower specific heats: aluminum 900, steel 490, copper 385 J/(kg·°C). This is why metal objects heat up and cool down much faster than water of the same mass. Iron cookware responds slowly to heat changes (thermal mass); thin stainless steel pans heat rapidly.
Heating water: the calorie connection
The original definition of a calorie: the energy needed to raise 1 gram of water by 1°C. So 1 calorie = 4.184 J. The food 'Calorie' (capital C) is actually 1 kilocalorie = 4,184 J.
Heating 1 liter (1 kg) of water from 20°C to 100°C: Q = 1 × 4,186 × 80 = 334,880 J ≈ 80 kcal. A kettle draws about 2,000 W, so this takes 334,880/2,000 ≈ 167 seconds — close to the 2.5-3 minutes we observe. This is Q = mcΔT in action every time you boil water for tea.
Advertisement
Phase changes and latent heat
The Q = mcΔT formula applies only when temperature is changing without a phase change. When water boils or ice melts, temperature stays constant while energy is absorbed or released as latent heat: Q = mL, where L is the latent heat (fusion for melting, vaporization for boiling).
Latent heat of fusion (ice melting): L_f = 334,000 J/kg. Latent heat of vaporization (water boiling): L_v = 2,260,000 J/kg. Boiling requires ~6.8× more energy than melting the same mass of ice. This is why steam burns are more severe than boiling water burns — steam releases its latent heat as it condenses on skin.
Tips & Insights
Water specific heat = 4,186 J/(kg·°C)
This is the default. For other materials: aluminum 900, steel 490, copper 385, iron 450, concrete 880, wood ~1,700, air 1,005 J/(kg·°C).
ΔT can be negative for cooling
If the material is losing heat (cooling), enter negative ΔT. Heat Q will be negative, indicating heat flows out of the system.
1 food Calorie = 4,184 J
Food labels use 'Calories' (kcal). A 500 Calorie meal provides 2,092,000 J of chemical energy — enough to heat 5 liters of water from 20°C to 100°C plus boil away some of it.
Worked Examples
Boiling a kettle
Q = 1 × 4,186 × 80 = 334,880 J = 80 kcal. This is the energy to bring 1 kg of water from 20°C to 100°C.
Heating an aluminum pan
Q = 0.5 × 900 × 200 = 90,000 J = 90 kJ. A 500g pan from room temp to 220°C needs 90 kJ.
Advertisement
Frequently Asked Questions
What is specific heat capacity?
The energy required to raise 1 kg of a substance by 1°C. Water: 4,186 J/(kg·°C). Higher specific heat = more energy needed to change temperature.
What is the difference between heat and temperature?
Temperature measures the average kinetic energy of particles. Heat is thermal energy transferred between objects. A large cold lake can contain more heat energy than a small hot cup of coffee.
What is a calorie?
1 calorie = 4.184 J. It's the energy to heat 1g of water by 1°C. Food 'Calories' (Cal) are kilocalories: 1 Cal = 4,184 J.
Why does water have such a high specific heat?
Water molecules form hydrogen bonds that must be broken to increase thermal motion. This requires more energy than for most other liquids or solids.
What happens at phase changes?
At melting and boiling points, temperature stays constant while latent heat is absorbed or released. Q = mcΔT doesn't apply during phase changes — use Q = mL instead.
Advertisement