Heat of Fusion Calculator
Enter mass and select a material (or enter a custom Lf value) to calculate the energy needed to melt or freeze it.
Inputs
Formula Reference
Q = m × Lf
- Q — heat energy (joules)
- m — mass (kg)
- Lf — specific latent heat of fusion (J/kg)
Enter mass and material, then click Calculate.
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joules (J)
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kilojoules (kJ)
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kilocalories (kcal)
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calories (cal)
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watt-hours (Wh)
Calculation Summary
Mass (m)
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Latent heat (Lf)
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Q = m × Lf
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Summary
Enter mass and select a material (or enter a custom Lf value) to calculate the energy needed to melt or freeze it.
How it works
- Enter the mass of the substance in kilograms or grams.
- Select a material from the preset list or choose "Custom" to enter your own Lf value.
- Choose the direction: melting (solid → liquid) or freezing (liquid → solid).
- The calculator applies Q = m × Lf and displays the energy in joules, kilojoules, and calories.
- Use the result to size heaters, coolers, or verify thermodynamics homework.
Use cases
- Calculate how much energy a furnace needs to melt a given mass of aluminum.
- Determine the heat a refrigeration system must remove to freeze water.
- Verify thermodynamics homework using the latent heat formula.
- Compare energy requirements for melting different metals.
- Estimate energy budgets for industrial casting or food processing.
- Understand phase-change energy in physics coursework.
Frequently Asked Questions
Last updated: 2026-06-10 ·
Reviewed by Nham Vu