How many BTU is 10,000 J?

10,000 ÷ 1055.056 = 9.48 BTU. About the energy in 10 sticks of butter.

Why does the US use BTU instead of kJ?

Historical convention — BTU predates metrication and remains embedded in US HVAC, appliances, and energy industries.

What's the difference between BTU and BTU (IT)?

BTU (IT) = 1055.056 J, defined in the International Steam Table. BTU (thermochemical) = 1054.350 J. The IT version is the modern standard.

A water heater is rated at 50,000 BTU — how many kJ?

50,000 × 1.055 = 52,750 kJ per hour. That's the heat output rating. For dietary energy, see [kilocalories to kilojoules](/energy/kcal-to-kj/).

Joules (J) to BTU (IT) Converter

Enter a value to instantly convert between energy units.

From

Precision4 dp

1 Joule = 0.0009 BTU (IT)

Key Formulas

Kilocalorie → Kilojoule

kJ = kcal × 4.184

Kilojoule → Kilocalorie

kcal = kJ × 0.239006

Kilowatt-Hour → Joule

J = kWh × 3600000

Joule → Kilowatt-Hour

kWh = J × 2.77778e-7

Formula

BTU = J ÷ 1055.056

A BTU (British Thermal Unit, IT version) is the energy to raise one pound of water by one degree Fahrenheit — about 1055 joules. BTU is common in US HVAC systems, water heater ratings, and heating equipment specifications. Converting joules to BTU means dividing by 1055. For the reverse conversion, see [BTU to joules](/energy/btu-to-joules/).

Source: NIST SP 811, Table B.8

Frequently Asked Questions

Real-World Examples

An HVAC technician verifying that 1055 J equals 1 BTU for the equipment manual.

1055 J = 1 BTU

A heating engineer calculating 5000 J from a furnace burner reports 4.74 BTU for the combustion analysis.

5000 J = 4.74 BTU

A boiler producing 21,100 J of heat per minute delivers 20 BTU/min for the spec sheet.

21100 J = 20 BTU

A student converting 1000 J to BTU for a thermodynamics problem gets 0.948 BTU.

1000 J = 0.948 BTU

kcal to kj kj to kcal kwh to joules joules to kwh btu to joules calories to joules

Joules (J) to BTU (IT) Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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