What is the base SI unit for fuel efficiency - mass?

The primary reference unit for fuel efficiency - mass in this converter is the Joule per Kilogram (J/kg). All 5 supported fuel efficiency - mass units are anchored to this standard.

Are these fuel efficiency - mass conversion factors verified?

Yes, all fuel efficiency - mass conversion constants on UnitConvertersGo are verified against NIST Special Publication 811 and ISO/IEC 80000 international metrology standards.

Fuel Efficiency - Mass Converter

Enter a value below to convert between metric, imperial, and standard fuel efficiency - mass units.

Convert Fuel Efficiency - Mass

Enter a value and select the units to convert between joules per kilogram, kilojoules per kilogram, and megajoules per kilogram.

Instant conversion

Value

From

Result

0.01 kJ/kg

10 J/kg = 0.01 kJ/kg

10 J/kg = 0.01 kJ/kg = 0.00001 MJ/kgGet Widget

You can change the units using the dropdowns above or click on a unit button.

Suggested Conversions

Common Fuel Efficiency - Mass Reference Points

Here are some common fuel efficiency - mass values in Joule per Kilogram (J/kg), Kilojoule per Kilogram (kJ/kg), and Megajoule per Kilogram (MJ/kg). Click any preset value or arrow to load it into the converter.

Description	Joule per Kilogram (J/kg)	Kilojoule per Kilogram (kJ/kg)	Megajoule per Kilogram (MJ/kg)
1 joule per kilogram unit	1	0.001	0.000001
5 joules per kilogram	5	0.005	0.000005
10 joules per kilogram benchmark	10	0.01	0.00001
25 joules per kilogram	25	0.025	0.000025
50 joules per kilogram	50	0.05	0.00005
100 joules per kilogram reference	100	0.1	0.0001

Fuel Efficiency - Mass Conversion Formulas

Use the following formulas to convert between joules per kilogram, kilojoules per kilogram, and megajoules per kilogram.

Joules per Kilogram to Kilojoules per Kilogram

kJ/kg = J/kg × 0.001

Kilojoules per Kilogram to Joules per Kilogram

J/kg = kJ/kg × 1,000

Joules per Kilogram to Megajoules per Kilogram

MJ/kg = J/kg × 0.000001

Example: Convert 10 Joules per Kilogram (J/kg) to Kilojoules per Kilogram (kJ/kg)

1 J/kg = 0.001 kJ/kg

10 J/kg × 0.001 = 0.01 kJ/kg

All fuel efficiency - mass conversions are anchored to the international SI base unit (Joule per Kilogram) for full scientific and engineering accuracy.

More Joule per Kilogram & Kilojoule per Kilogram Conversions

Convert from Joules per Kilogram

Convert to Kilojoules per Kilogram

Frequently Asked Questions

1 joule per kilogram (J/kg) equals 0.001 kilojoules per kilogram (kJ/kg). Multiply your joule per kilogram value by 0.001 or enter it in the Fuel Efficiency - Mass Converter above for instant calculation.

Fuel Efficiency - Mass Converter

Quick Info

Joule per Kilogram (J/kg) is a primary fuel efficiency - mass unit used globally across science, commerce, and daily measurement.
Kilojoule per Kilogram (kJ/kg) is widely used alongside J/kg for practical fuel efficiency - mass specifications and conversions.
Joule per Kilogram (J/kg) serves as the standardized reference base unit anchoring all 5 units in this category.
Verified accuracy: All conversion factors follow official NIST SP 811 and ISO/IEC 80000 metrology constants.

Fuel Efficiency - Mass Units Comparison

Joule per Kilogram (J/kg)

SI unit of specific energy.

Kilojoule per Kilogram (kJ/kg)

Equal to 1,000 J/kg.

Megajoule per Kilogram (MJ/kg)

Standard fuel heating value unit (1,000,000 J/kg).

References

[1]NIST · NIST HB 133 / SP 811
Source
[2]BIPM · BIPM SI-9
Source
[3]NIST SP 811 · NIST SP 811 App. B.9
Source

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All Fuel Efficiency - Mass Conversion Calculators (6)

Select any dedicated fuel efficiency - mass pair below for worked examples and printable tables

Joules per Kilogram to Kilojoules per Kilogram (J/kg to kJ/kg)Kilojoules per Kilogram to Joules per Kilogram (kJ/kg to J/kg)Joules per Kilogram to Megajoules per Kilogram (J/kg to MJ/kg)Megajoules per Kilogram to Joules per Kilogram (MJ/kg to J/kg)Joules per Kilogram to Calories per Gram (J/kg to cal/g)Calories per Gram to Joules per Kilogram (cal/g to J/kg)

Category Conversion Matrix

Simultaneous comparison of 5 units in this category

Joule per Kilogram (J/kg)

Kilojoule per Kilogram (kJ/kg)

0.001

Megajoule per Kilogram (MJ/kg)

0.000001

Calorie (IT) per Gram (cal/g)

0.00023884

BTU per Pound (BTU/lb)

0.00042992

Fuel Efficiency - Mass Unit Definitions & Symbols

Joule per Kilogram (J/kg)

SI unit of specific energy.

Kilojoule per Kilogram (kJ/kg)

METRIC

Equal to 1,000 J/kg.

Megajoule per Kilogram (MJ/kg)

METRIC

Standard fuel heating value unit (1,000,000 J/kg).

Calorie (IT) per Gram (cal/g)

METRIC

Equal to 4,186.8 J/kg (1 kcal/kg).

BTU per Pound (BTU/lb)

US CUSTOMARY

Imperial/US fuel specific heating value (1 BTU/lb = 2,326 J/kg).

References

NIST · BIPM · ISO

[1]
NIST (NIST HB 133 / SP 811)·Checking the Net Contents of Packaged Goods, Handbook 133 - 2019 Edition & NIST SP 811
NIST HB 133 Standard
[2]
BIPM (BIPM SI-9)·The International System of Units (SI Brochure, 9th Edition)
BIPM SI Brochure
[3]
NIST SP 811 (NIST SP 811 App. B.9)·NIST Guide to the SI, Appendix B.9: Factors for Units Listed by Kind of Quantity or Field of Science
NIST SP 811 Appendix B.9

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Fuel Efficiency - Mass

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