Energy Converter 2026 | Joules ↔ Calories ↔ kWh ↔ BTU ↔ eV | Global Tool

An Energy Converter helps you convert between common energy units such as joules (J), kilojoules (kJ), calories (cal), kilocalories (kcal), watt-hours (Wh), kilowatt-hours (kWh), British Thermal Units (BTU), and electronvolts (eV). It’s useful for physics, engineering, electrical calculations, HVAC systems, and nutrition-related energy comparisons. This tool is designed for educational and reference use.

The SI (International System) unit of energy is the joule (J). Larger values are often expressed as kilojoules (kJ) or megajoules (MJ). Joules are widely used in physics, engineering, and scientific calculations around the world.

To convert joules (J) to kilojoules (kJ), divide by 1,000. Example: 50,000 J = 50 kJ. This conversion is common in science, energy labels, and many international nutrition systems.

To convert joules (J) to small calories (cal), divide by 4.184. Example: 4184 J ≈ 1000 cal. Note: this is the physics calorie (small cal), not the food Calorie used in nutrition labels.

A calorie (cal) is a small unit of energy, while 1 kilocalorie (kcal) equals 1,000 calories (cal). In nutrition, 1 “food Calorie” (with a capital C) is actually 1 kilocalorie (kcal). Brutally honest: this naming confusion is one of the most common reasons people misunderstand nutrition labels.

Yes. In nutrition, 1 Calorie (capital C) = 1 kilocalorie (kcal). Example: 250 Calories on a food label means 250 kcal. This is standard globally, including India, USA, UK, Canada, Australia, UAE and most regions.

To convert kilowatt-hours (kWh) to joules (J), multiply by 3,600,000 (3.6 × 10^6). Example: 1 kWh = 3,600,000 J. This conversion is common in electrical energy calculations and power billing.

Wh (watt-hour) and kWh (kilowatt-hour) measure electrical energy. 1 kWh = 1,000 Wh. Utility electricity bills typically use kWh because it represents larger amounts of energy consumption more conveniently.

BTU (British Thermal Unit) is a traditional energy unit commonly used in HVAC and heating/cooling systems. It is widely used in countries like the USA and in global air-conditioner specifications. BTU values help estimate heating/cooling capacity rather than electricity consumption.

To convert BTU to joules, multiply by approximately 1055.06. Example: 10,000 BTU ≈ 10,550,600 J. This is useful in engineering, thermodynamics, and HVAC calculations.

To convert kWh to BTU, multiply by approximately 3412.14. Example: 2 kWh ≈ 6824 BTU. This conversion is often used when comparing electrical energy usage with heating/cooling energy output.

Yes. A reliable energy converter uses standard international conversion constants (SI/engineering references). Results are accurate for scientific calculations, education, engineering comparisons, and general estimation. For high-precision industrial applications, always follow official engineering standards and rounding rules.