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❄️ Latent Heat Calculator

Calculate the amount of energy needed to melt, freeze, boil, or condense a given mass of a substance using its specific latent heat.

kg
kJ/kg

What This Calculator Does

Latent heat is the energy absorbed or released during a phase change (like melting, freezing, boiling, or condensing) without a change in temperature. This calculator finds the total energy involved for a given mass of substance.

The Formula

The formula is simply Q = m × L, where m is mass in kilograms and L is the specific latent heat of the substance in kJ/kg. Water’s specific latent heat of fusion (melting/freezing) is about 334 kJ/kg, and its specific latent heat of vaporization (boiling/condensing) is about 2260 kJ/kg at standard atmospheric pressure.

Note: For substances other than water, use the custom option and enter the correct specific latent heat value for that material and phase change, since these vary widely between substances.

Last reviewed August 2026