Specific Heat Calculator
Enter any three of heat, mass, specific heat capacity and temperature change. You get the fourth. A menu fills in common materials.
Fill in three of the four values and leave the one you want to find empty. The answer appears as you type, in the unit shown next to its box. Material values are typical figures at room temperature.
Worked examples
Kettle
1 kg water heated by 80 K
334,720 J (334.7 kJ)
1 x 4184 x 80.
Copper
3,850 J into 0.5 kg raising it 20 K
385 J per kilogram per kelvin
3850 / (0.5 x 20).
About Specific Heat Calculator
Specific heat capacity is the amount of energy needed to raise the temperature of one kilogram of a material by one kelvin. Water needs 4,184 joules, which is high, so it heats and cools slowly. Metals such as copper at 385 joules need far less, so they heat up fast. The heat needed is the mass, multiplied by the specific heat, multiplied by the temperature change, and this calculator solves for any one of the four quantities.
A menu fills in typical specific heats for water, ice, steam, aluminium, copper, iron, lead, glass, air and ethanol. Enter the power of a heater and the page also estimates how long the heating takes, assuming no heat losses. Energy is shown in joules, kilojoules, kilowatt hours and calories. It assumes there is no change of state, such as boiling or melting, which needs extra energy called latent heat.
How to use Specific Heat Calculator
- Fill in three of heat, mass, specific heat capacity and temperature change.
- Pick a material from the menu to fill in its specific heat, or type your own value.
- Optionally enter a heater power to see an approximate time.
- Read the missing value and the heat in other units.
Common uses
- Working out the energy to heat a kettle or tank of water
- Estimating how long an immersion heater takes
- Identifying a metal from the heat it absorbs in an experiment
- Comparing how quickly different materials warm up
Frequently asked questions
What is the specific heat formula?
Q = m x c x delta T, where Q is the heat in joules, m is the mass in kilograms, c is the specific heat capacity and delta T is the temperature change.
How much energy does it take to heat water?
It takes 4,184 joules to warm one kilogram of water by one degree. Heating one litre from 20 to 100 degrees takes about 335 kilojoules, or 0.093 kilowatt hours.
Is a change of one degree Celsius the same as one kelvin?
Yes. They are the same size, so you can use either for a temperature change. Fahrenheit changes are smaller, by a factor of 5/9.
Why is the heating time only approximate?
The estimate divides the heat by the heater's power and ignores heat lost to the surroundings, which makes real heating slower.