# Latent Heat Calculator

The latent heat calculator helps you compute the **energy released or absorbed during a phase transition like melting or vaporizing**. In the text below, we explain what is specific latent heat and present a simple latent heat calculation.

## Specific latent heat

Specific latent heat is energy hidden in the internal structure of a substance. As we saw in the sensible heat calculator, if we transfer heat to water, its temperature increases according to its specific heat.

Once the temperature reaches the boiling point, something interesting happens. **The temperature stops increasing, and instead, the water vaporizes.** This process of turning water into vapor takes some energy. This is the latent heat. Once all the water is turned into vapor, a further transfer of heat will simply increase the temperature again.

**Condensation** is the reverse process of vaporization, where gas turns into liquid. The latent heat released during condensation is equal to the latent heat absorbed during vaporization.

A change from a liquid to a gaseous phase is an example of a **phase transition**. Another common phase transition is from a solid to a liquid phase. **Specific latent heat** is the amount of energy absorbed or released during the phase transition per `1 kg`

of the substance.

🔎 If you need to know the **temperature at which the phase transition occurs**, make sure to check our boiling point calculator.

## Latent heat calculation

All we need to know to compute the latent heat is the amount of substance and its specific latent heat. The formula is:

where:

- $m\ \rm [kg]$ — Mass of the body;
- $L\ \rm [kJ/kg]$ — Specific latent heat; and
- $Q\ \rm [kJ]$ — Heat absorbed or released depending on the direction of the transition.

The specific latent heat is different for solid-to-liquid transition and liquid-to-gas transition. For example, if we want to turn $\small 20\ \rm g$ of ice into water, we need $\small Q = 20\ \rm g \times 334\ kJ/kg = 6680\ J$ of energy. To turn the same amount of water into vapor, we need $\small Q = 45294\ \rm J$.

## Latent heat calculator

Our calculator makes the computation of latent heat simple. It provides the specific latent heat for a few substances. If the substance that you're after is not on the list, just select the **Other** option and input your own specific latent heat below it.

It's amusing to observe that it takes less energy to go from solid-state to liquid phase than to go from liquid phase to gas. It means that **liquids are more like solids than gases**.

### How to calculate latent heat?

To calculate latent heat, you need to multiply two numbers:

**Specific latent heat**, the energy absorbed or released during a phase transition per kilogram of substance; and- The
**mass**of the substance.

`latent heat = specific latent heat × mass`

### What is the difference between latent heat, and specific latent heat?

**Latent heat** is the **total energy** released or absorbed during a phase transition of a substance.

**Specific latent heat**, on the other hand, is the energy released or absorbed during a substance's phase transition **per 1 kilogram**.

### What is the difference between latent heat and specific heat capacity?

**Latent heat** is the total energy released or absorbed **during a phase transition** of a substance. You find it by multiplying the specific latent heat of a substance by its mass. It's also known as the heat of transformation.

**Specific heat capacity** is the energy released or absorbed with the **change in temperature by exactly 1 kelvin per 1 kilogram of substance**. The same substance has different heat capacities in different phases (i.e., water and ice).

### What is the latent heat of the fusion of 5 kg of water?

The latent heat of the fusion of `5 kg`

of water is `1670 kJ`

. To find this number on your own, you need to multiply the specific latent heat of the fusion of water (`334 kJ/kg`

) times the mass of the water (`5 kg`

).

`latent heat = specific latent heat × mass`