Fuel Efficiency (mass) Converter
Fuel efficiency by mass — specific energy — is how much energy a kilogram of fuel releases. Energy-per-mass units such as joules per kilogram and BTU per pound rise with better fuel; the reciprocal family (grams per kilowatt-hour, pounds per horsepower-hour) is engine brake-specific fuel consumption, where lower is better.
16 units supported Base unit joule per kilogram (J/kg)
Multiply the number of joules per kilogram by 0.001 to get kilojoules per kilogram. How this is calculated
About fuel efficiency (mass) conversion
Fuel Efficiency (mass) conversion is commonly needed when engine testing, fuel specification, and combustion analysis. Energy-per-mass figures rise with better fuel, while brake-specific consumption in grams per kilowatt-hour falls — they are reciprocals.
Convert Joule per Kilogram to other fuel efficiency (mass) units
1 J/kg expressed in every other fuel efficiency (mass) unit on this site.
- Joule per Kilogram J/kg 1
- Kilojoule per Kilogram kJ/kg 0.001
- Megajoule per Kilogram MJ/kg 0.000001
- Calorie (IT) per Gram cal(IT)/g 0.0002388459
- Calorie (th) per Gram cal(th)/g 0.00023900574
- BTU (IT) per Pound BTU/lb 0.00042992261
- BTU (th) per Pound BTU(th)/lb 0.00043021033
- Kilogram per Joule kg/J 1
- Kilogram per Kilojoule kg/kJ 1,000
- Gram per Calorie (IT) g/cal(IT) 4,186.8
- Gram per Calorie (th) g/cal(th) 4,184
- Pound per BTU (IT) lb/BTU 2,326
- Pound per BTU (th) lb/BTU(th) 2,324.4444
- Pound per Horsepower-hour lb/(hp·h) 5,918,352.5
- Gram per Horsepower-hour (metric) g/(PS·h) 2,647,795,500
- Gram per Kilowatt-hour g/kWh 3,600,000,000
Complete list of fuel efficiency (mass) units
All 16 units this converter supports, each stated against the joule per kilogram (J/kg).
| Unit | Symbol | System | In joules per kilogram | Conversions |
|---|---|---|---|---|
| Joule per Kilogram | J/kg | SI | base unit (J/kg) | — |
| Kilojoule per Kilogram | kJ/kg | SI | 1 kJ/kg = 1,000 J/kg | — |
| Megajoule per Kilogram | MJ/kg | SI | 1 MJ/kg = 1,000,000 J/kg | — |
| Calorie (IT) per Gram | cal(IT)/g | Metric | 1 cal(IT)/g = 4,186.8 J/kg | — |
| Calorie (th) per Gram | cal(th)/g | Metric | 1 cal(th)/g = 4,184 J/kg | — |
| BTU (IT) per Pound | BTU/lb | Imperial | 1 BTU/lb = 2,326 J/kg | — |
| BTU (th) per Pound | BTU(th)/lb | Imperial | 1 BTU(th)/lb = 2,324.44444444 J/kg | — |
| Kilogram per Joule | kg/J | SI | 1 kg/J = 1 J/kg (non-linear scale) | — |
| Kilogram per Kilojoule | kg/kJ | SI | 1 kg/kJ = 1,000 J/kg (non-linear scale) | — |
| Gram per Calorie (IT) | g/cal(IT) | Metric | 1 g/cal(IT) = 4,186.8 J/kg (non-linear scale) | — |
| Gram per Calorie (th) | g/cal(th) | Metric | 1 g/cal(th) = 4,184 J/kg (non-linear scale) | — |
| Pound per BTU (IT) | lb/BTU | Imperial | 1 lb/BTU = 2,326 J/kg (non-linear scale) | — |
| Pound per BTU (th) | lb/BTU(th) | Imperial | 1 lb/BTU(th) = 2,324.4444 J/kg (non-linear scale) | — |
| Pound per Horsepower-hour | lb/(hp·h) | Imperial | 1 lb/(hp·h) = 5,918,352.5 J/kg (non-linear scale) | — |
| Gram per Horsepower-hour (metric) | g/(PS·h) | Metric | 1 g/(PS·h) = 2,647,795,500 J/kg (non-linear scale) | — |
| Gram per Kilowatt-hour | g/kWh | SI | 1 g/kWh = 3,600,000,000 J/kg (non-linear scale) | — |
No unit in this category matches that search.
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Frequently asked questions
What is the base unit for fuel efficiency (mass)?
Fuel Efficiency (mass) conversions on this site are calculated against the joule per kilogram (J/kg).
Which fuel efficiency (mass) units can I convert?
You can convert between 16 units, including joule per kilogram, kilojoule per kilogram, megajoule per kilogram, calorie (it) per gram, and more.
Where is fuel efficiency (mass) conversion useful?
It is commonly needed when engine testing, fuel specification, and combustion analysis.
Does this converter mix measurement systems?
The converter supports SI, Metric, Imperial units and keeps their exact definitions separate so results stay accurate.
Related categories
Conversion factors are based on internationally agreed unit definitions. See our methodology and sources for details on how these values are verified.