Convert energy units — joules, calories, kilowatt-hours, BTU, kilojoules.
| Unit | Name | Value |
|---|---|---|
| J | Joule | 3600000 |
| kJ | Kilojoule | 3600 |
| cal | Calorie | 860420.65 |
| kcal | Kilocalorie (Cal) | 860.42065 |
| BTU | BTU | 3412.1282 |
Formula: Joule = Kilowatt-Hour × 3.6e+06
Multiply any kilowatt-hour value by 3.6e+06 to get joule.
Reverse: Kilowatt-Hour = Joule × 2.7778e-7
Common kilowatt-hour values — factor: 1 kWh = 3.6e+06 J
| Kilowatt-Hour (kWh) | Joule (J) | Context |
|---|---|---|
| 0.001 kWh | 3,600 J | 1 Wh |
| 0.01 kWh | 3.6e+04 J | 10 Wh |
| 0.1 kWh | 3.6e+05 J | Phone charge |
| 0.5 kWh | 1.8e+06 J | Half kWh |
| 1 kWh | 3.6e+06 J | 1 kWh |
| 5 kWh | 1.8e+07 J | 5 kWh |
| 10 kWh | 3.6e+07 J | Washing machine |
| 30 kWh | 1.08e+08 J | Daily home use |
| 100 kWh | 3.6e+08 J | Monthly fraction |
| 500 kWh | 1.800e+09 J | EV range |
| 1,000 kWh | 3.600e+09 J | Monthly home |
| 1e+04 kWh | 3.600e+10 J | Annual home |
| 1e+05 kWh | 3.600e+11 J | Large commercial |
| 1e+06 kWh | 3.600e+12 J | Small factory |
| 1.000e+09 kWh | 3.600e+15 J | Power plant day |
kWh × 3,600,000 = J. Exact: 1 kWh = 1000W × 3600s = 3,600,000 J.
Multiply kWh by 3.6 million — or by 3.6 to get megajoules first.
J ÷ 3,600,000 = kWh.
Reads monthly bills and compares appliance energy use in kWh.
Sizes solar systems based on kWh consumption and production estimates.
Tracks charging cost and range efficiency in kWh per 100 km.
Measures building energy consumption and identifies savings in kWh.
Plans grid capacity, demand response, and billing in kWh and MWh.
Monitors real-time appliance consumption in kWh via smart meters.
The kilowatt-hour (kWh) is the commercial unit of electrical energy, equal to the energy consumed by a 1,000-watt appliance in one hour (3,600,000 joules). It became standard with the growth of the electrical grid in the late 19th century.
Electricity bills worldwide are denominated in kWh. A typical household uses 300–1,000 kWh per month. An electric car uses about 15–25 kWh per 100 km. Solar panels generate 250–400 kWh per year per panel.
Interesting fact: The average price of electricity in the US is about $0.12 per kWh. One kWh can run a 100W light bulb for 10 hours, charge a smartphone about 100 times, or power a laptop for 2-3 days.
The joule is the SI derived unit of energy, work, and heat, defined as the energy transferred when a force of one newton moves an object one meter. It was named after James Prescott Joule, the English physicist who established the mechanical equivalent of heat in the 1840s.
The joule is universal in physics and engineering: kinetic energy (½mv²), potential energy (mgh), electrical energy (VIt), and heat are all measured in joules. One joule is the energy needed to lift a 100g apple one meter against gravity.
Interesting fact: The human heart expends about 1 joule of energy with each beat. A 60-watt light bulb uses 60 joules every second. The entire energy released by a 1-megaton nuclear weapon equals about 4.18 × 10¹⁵ joules.
Converting kilowatt-hour to joule 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 kWh = 1.8e+07 J and 10 kWh = 3.6e+07 J. Reverse: 1 J = 2.7778e-7 kWh. Exact factor: 1 kWh = 3.6e+06 J.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.