FreeUnitConverter
Home/Heat and Thermodynamics Converters

Specific Energy Converter

Convert specific energy units including J/kg, kJ/kg, Wh/kg, cal/g, BTU/lb, ft-lbf/slug, and lb-ft/lb instantly - energy per mass, no signup. Ideal for battery engineers, fuel analysis, and aerospace calculations.

0.429923
1 kJ/kg = 0.429923 BTU IT/lb
Formula: 1 kJ/kg = 1000 J/kg; 1 Wh/kg = 3600 J/kg; 1 cal(IT)/g = 4186.8 J/kg; 1 BTU(IT)/lb ≈ 2326 J/kg.

Recommended Tools

About this specific energy converter

Convert specific energy units for fuels, batteries, propellants, thermal storage materials, and energy-per-mass engineering comparisons.

Specific energy measures energy per unit mass, which is different from volumetric energy density measured per unit volume.

Units covered

Specific energy units

J/kg, kJ/kg, Wh/kg, cal/g, BTU/lb, ft·lbf/slug, and lb·ft/lb.

Fuel and battery work

Helpful for comparing gasoline, hydrogen, lithium-ion cells, fuels, and propellants by mass.

Standard variants

Includes IT and thermochemical calorie and BTU definitions for precise source matching.

How to use it

  • Enter the energy-per-mass value.
  • Select the source unit and target unit.
  • Convert all materials to a common unit before comparing fuel or battery performance.

Frequently Asked Questions