Convert Grams per Calorie (IT) to Joules per Kilogram
Gram per Calorie (IT) (g/cal) to Joule per Kilogram (J/kg) mass-basis fuel efficiency conversion — enter any value below to get an instant result, or use the table for common values.
Results from this calculator are estimates provided for general informational purposes only, based on formulas, rates, and standards commonly accepted as of 2026. Figures may differ slightly from other calculators or professional sources due to rounding methods, differing assumptions, or regional regulations, and rules may change over time. Always consult a qualified professional — such as a financial advisor, healthcare provider, or other relevant specialist — before making decisions based on these results.
Result
1 g/cal = 4186.8 J/kg
1 Gram per Calorie (IT) = 4186.8 Joules per Kilogram
1 Joule per Kilogram = 4186.8 Grams per Calorie (IT)
1 g/cal in every supported unit
Conversion chart: Gram per Calorie (IT) to Joules per Kilogram
Conversion table
| Gram per Calorie (IT) (g/cal) | Joule per Kilogram (J/kg) |
|---|---|
| 0.01 g/cal | 418680 J/kg |
| 0.1 g/cal | 41868 J/kg |
| 1 g/cal | 4186.8 J/kg |
| 2 g/cal | 2093.4 J/kg |
| 3 g/cal | 1395.6 J/kg |
| 5 g/cal | 837.36 J/kg |
| 10 g/cal | 418.68 J/kg |
| 20 g/cal | 209.34 J/kg |
| 50 g/cal | 83.736 J/kg |
| 100 g/cal | 41.868 J/kg |
| 1000 g/cal | 4.1868 J/kg |
Gram per Calorie (IT) (g/cal)
Definition: A specific fuel consumption unit expressing how many grams of fuel mass are needed to deliver one calorie of energy — the reciprocal of calories per gram.
History: A natural inversion of the calorie-per-gram calorific value unit, used wherever a mass-budgeting rather than energy-content framing is more convenient.
Current use: Occasionally used in laboratory and small-scale process calculations that need fuel or reactant mass expressed directly per unit of heat delivered.
Joule per Kilogram (J/kg)
Definition: The SI derived unit of specific energy — how many joules of energy are released by burning (or otherwise extracting energy from) one kilogram of a fuel or material.
History: A direct combination of the SI joule and kilogram, adopted as the coherent scientific unit for specific energy once both base units were standardized internationally.
Current use: Used in physics and engineering calculations of calorific value, battery energy density, and food energy content wherever SI-consistent units are required throughout a larger calculation.
Supported Units
| Unit | Symbol | Category |
|---|---|---|
| Joule per Kilogram | J/kg | Specific energy (energy/mass) |
| Kilojoule per Kilogram | kJ/kg | Specific energy (energy/mass) |
| Calorie (IT) per Gram | cal/g | Specific energy (energy/mass) |
| Btu (IT) per Pound | Btu/lb | Specific energy (energy/mass) |
| Kilogram per Kilojoule | kg/kJ | Specific fuel consumption (mass/energy) |
| Gram per Calorie (IT) | g/cal | Specific fuel consumption (mass/energy) |
| Pound per Btu (IT) | lb/Btu | Specific fuel consumption (mass/energy) |
| Pound per Horsepower-hour | lb/(hp·h) | Specific fuel consumption (mass/energy) |
| Gram per Kilowatt-hour | g/kWh | Specific fuel consumption (mass/energy) |
About These Parameters
- Value
- The fuel-efficiency figure you want to convert, expressed in the "From" unit. Accepts decimals.
- From Unit
- The unit your input value is currently measured in — a specific-energy unit like J/kg or Btu/lb, or an engine SFC unit like g/kWh.
- To Unit
- The unit you want the result converted into. Use the swap button to flip From and To instantly.
How Fuel Efficiency - Mass Conversion Works
The Formula
Within the same group (both specific energy, or both specific fuel consumption), conversion is a simple multiplication:
result = value × (factor of "From" unit ÷ factor of "To" unit)
Crossing between the two groups instead inverts through the base unit:
SFC unit = (factor of SFC unit) ÷ (value × factor of specific-energy unit)
For Gram per Calorie (IT) → Joule per Kilogram: 1 g/cal = 4186.8 J/kg.
Specific Energy vs. Specific Fuel Consumption
Specific energy (J/kg, cal/g, Btu/lb) describes a fuel's raw calorific value — an intrinsic property of the fuel itself, independent of any engine. Specific fuel consumption (g/kWh, lb/(hp·h)) instead describes how efficiently a real engine turns that stored energy into usable mechanical output, and depends on the engine's thermal efficiency, not just the fuel. A lower SFC figure always means a more fuel-efficient engine, the opposite direction from specific energy, where a higher figure means a more energy-dense fuel.
Why g/kWh Replaced lb/(hp·h)
Pounds per horsepower-hour was the standard engine efficiency rating through the early-to-mid 20th century, when horsepower was the universal power unit in aviation and marine engineering. As engine testing and international trade shifted to the metric kilowatt, grams per kilowatt-hour became the global standard — it's the figure printed on virtually every modern diesel and gasoline engine's technical datasheet today.
Example
A diesel engine rated at 200 g/kWh converts to about 0.32879736 lb/(hp·h) — a typical figure for a modern, efficient diesel; older or smaller gasoline engines often run well above 250 g/kWh.
Frequently Asked Questions
How many Joules per Kilogram are in 1 Gram per Calorie (IT)?
1 Gram per Calorie (IT) (g/cal) equals exactly 4186.8 Joules per Kilogram (J/kg).
Why does a lower g/kWh mean a better engine, when higher J/kg means a better fuel?
They measure different things in opposite directions. J/kg (specific energy) is a property of the fuel — more energy per kilogram is always better. g/kWh (specific fuel consumption) is a property of the engine — it asks how much fuel mass is spent to deliver one unit of output, so less fuel for the same output means a more efficient engine.
Can I convert a fuel's calorific value directly into an engine's SFC rating?
This converter performs the mathematical reciprocal between the two groups, but that number alone assumes a perfectly (100%) efficient engine. Real engines lose energy to heat, friction, and exhaust, so an actual SFC rating is always numerically worse (higher) than the theoretical reciprocal of the fuel's calorific value.
How accurate are these conversions?
Every conversion factor used here is the exact, internationally recognized relationship between the underlying energy, mass, and power units (e.g. 1 kWh = exactly 3,600,000 joules) — results are limited only by floating-point display precision, not by rounded conversion constants.