Physics
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Latent Heat Calculator.
Calculate phase-change heat from mass and specific latent heat.
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01
Set your values
Results update as you type.
02 / ANSWER
Heat: 668,000 J
Results update automatically as you type.
Use Cases
Physics homework and exam prep
Quickly verify calculations for phase change problems, ensuring correct use of mass and latent heat values.
Example: Calculate heat needed to melt 2 kg of ice (L = 334,000 J/kg).
Engineering and design calculations
Estimate energy requirements for processes involving melting, freezing, or vaporization in industrial or experimental setups.
Example: Determine heat required to vaporize 5 kg of water (L = 2,260,000 J/kg).
Frequently Asked Questions
- What is specific latent heat?
- Specific latent heat is the amount of heat energy required to change the phase of 1 kilogram of a substance without changing its temperature. It is measured in joules per kilogram (J/kg).
- How do I use this latent heat calculator?
- Enter the mass of the substance in kilograms and its specific latent heat in J/kg. The calculator multiplies them to give the total heat energy in joules (J).
- Can this calculator be used for both melting and boiling?
- Yes, the formula Q = m * L applies to any phase change, such as melting (fusion) or boiling (vaporization), as long as you use the appropriate specific latent heat value for that transition.
Tips & Common Mistakes
Tips
- Ensure mass is in kilograms and specific latent heat is in J/kg to get the result in joules.
- Use the correct latent heat value for the specific phase change (fusion vs. vaporization).
- Remember that temperature remains constant during a phase change; this calculator only accounts for the energy of the phase transition.
- For multi-step processes, calculate the sensible heat separately and add it to the latent heat.
Common Mistakes to Avoid
- Using grams instead of kilograms for mass, leading to results off by a factor of 1000.
- Confusing specific latent heat with specific heat capacity, which involves temperature change.
- Forgetting to convert units if the latent heat is given in kJ/kg instead of J/kg.
Last updated: August 13, 2026