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Unit Conversion
Energy Density Converter
Convert energy density accurately in mass-based and volume-based units. Compare batteries and bridge the two only with known material density.
Energy per volume
Result—
Calculation
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All equivalent values
Energy per mass
Result—
Calculation
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All equivalent values
Convert between mass and volume
A positive material density is required; without it, these are different dimensions.
Wh/kg → Wh/L—
Wh/L → Wh/kg—
Calculation
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Compare two batteries
A and B are editable examples, not measurements of real batteries. Compare the same cell/pack level and nominal/usable energy basis.
A
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B
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Wh/kg versus Wh/L
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Right means more energy per mass; higher means more energy per volume.
Calculation
E/V = (E/m) × ρ · E/m = (E/V) ÷ ρ · ρ = kg/L
IT calorie and IT BTU use their named definitions; kcal/g uses the thermochemical kilocalorie.
Volumetric vs gravimetric energy density
Energy density can describe energy per volume or energy per mass. Mixing those two categories is a common source of mistakes.
- Volumetric energy density uses units like Wh/L or J/m3.
- Gravimetric energy density uses units like Wh/kg or MJ/kg.
- Convert within the same category unless density is also known.
Battery, fuel, and material comparisons
Use this converter for battery specs, fuel comparisons, thermal storage, food energy, and engineering calculations.
- Battery articles often use Wh/kg and Wh/L.
- Fuel tables often use MJ/kg or MJ/L.
- Food energy may use kcal/g or kJ/g.
Related calculators
Energy density often connects to energy, density, power, and electricity cost.
Energy Density Converter FAQ
What is energy density?
Energy density measures how much energy is stored in a given volume or mass.
What is the difference between Wh/kg and Wh/L?
Wh/kg measures energy per mass. Wh/L measures energy per volume.
Can I convert Wh/kg to Wh/L directly?
Not directly unless you also know the material density. Mass-based and volume-based energy density are different categories.
Why do batteries use energy density?
Energy density helps compare how much energy a battery stores for its weight or size.
Is kcal/g an energy density unit?
Yes. Calories per gram is a mass-based energy density unit often used for food and fuel comparisons.
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