Convert energy units — joules, calories, kilowatt-hours, BTU, kilojoules.
| Unit | Name | Value |
|---|---|---|
| J | Joule | 1000 |
| cal | Calorie | 239.00574 |
| kcal | Kilocalorie (Cal) | 0.23900574 |
| kWh | Kilowatt-hour | 0.00027777778 |
| BTU | BTU | 0.94781339 |
Formula: BTU = Kilojoule × 0.9478
Multiply any kilojoule value by 0.9478 to get btu.
Reverse: Kilojoule = BTU × 1.055
Common kilojoule values — factor: 1 kJ = 0.9478 BTU
| Kilojoule (kJ) | BTU (BTU) | Context |
|---|---|---|
| 0.001 kJ | 0.0009478 BTU | 1 J |
| 0.01 kJ | 0.009478 BTU | 10 J |
| 0.1 kJ | 0.09478 BTU | 100 J |
| 1 kJ | 0.9478 BTU | 1 kJ |
| 4.184 kJ | 3.966 BTU | 1 kcal |
| 10 kJ | 9.478 BTU | 10 kJ |
| 100 kJ | 94.78 BTU | 100 kJ |
| 1,000 kJ | 947.8 BTU | 1 MJ |
| 3,600 kJ | 3,412 BTU | 1 kWh |
| 1e+04 kJ | 9,478 BTU | 10 MJ |
| 1e+05 kJ | 9.478e+04 BTU | 100 MJ |
| 1e+06 kJ | 9.478e+05 BTU | 1 GJ |
| 1e+08 kJ | 9.478e+07 BTU | 100 GJ |
| 1.000e+10 kJ | 9.478e+09 BTU | 10 TJ |
| 1.000e+12 kJ | 9.478e+11 BTU | 1 PJ |
kJ × 0.9478 = BTU. Round to × 0.95.
One kilojoule is slightly less than one BTU.
BTU × 1.055 = kJ.
Labels food energy in kJ for metric-market nutritional information.
Calculates reaction heat, enthalpy changes, and process energy in kJ.
Measures athlete metabolic rate and substrate oxidation in kJ.
Teaches heat transfer, steam tables, and engine cycles using kJ.
Prescribes energy intake using kJ in countries using metric labels.
Calculates heat duty for reactors, heat exchangers, and distillation in kJ.
The kilojoule (kJ) equals 1,000 joules and is the practical energy unit for food, chemistry, and heating applications in metric countries. Food energy labels in Australia, Europe, and most of the world use kilojoules.
A dietary calorie (kcal) equals 4.184 kJ. A can of soda contains about 600 kJ. The specific heat of water (4.184 kJ/kg·°C) means heating 1 liter of water by 1°C requires 4.184 kJ.
Interesting fact: An average adult needs about 8,000-10,000 kJ (2,000-2,400 kcal) per day. Running a marathon burns approximately 12,500 kJ.
The British Thermal Unit (BTU) is the traditional Imperial energy unit, defined as the heat required to raise 1 pound of water by 1°F. It equals 1,055.06 joules and has been used since the 19th century in heating, air conditioning, and gas billing.
BTU remains dominant in US HVAC: air conditioners and heaters are rated in BTU/hour. Natural gas is priced in therms (100,000 BTU) in the US. Furnaces are rated in BTU/hour output.
Interesting fact: A typical US home furnace is rated at 80,000–120,000 BTU/hour. One BTU is roughly the energy released by burning one kitchen match. The US natural gas pipeline system delivers about 25 quadrillion BTU (quads) per year.
Converting kilojoule to btu is common across energy, nutrition, engineering, and science. Different sectors use different energy units — joules in physics, kcal in nutrition, kWh in electricity, and BTU in HVAC — making accurate conversion essential for cross-disciplinary work and international comparisons.
Quick reference: 5 kJ = 4.739 BTU and 10 kJ = 9.478 BTU. Reverse: 1 BTU = 1.055 kJ. Exact factor: 1 kJ = 0.9478 BTU.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.