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Energy Converter

Convert between different energy units (joules, calories, kWh, BTUs, etc.) instantly with precision.

From

Popular Conversions

Quick Reference Table

Joule (J)	Kilojoule (kJ)
1 J	1000 kJ
5 J	5000 kJ
10 J	10000 kJ
50 J	50000 kJ
100 J	100000 kJ
500 J	500000 kJ
1000 J	1000000 kJ

How to Convert

1. Enter the value you want to convert in the From or To input box.

2. Select the corresponding units from the dropdown menus below the input boxes.

3. The conversion calculates instantly and dynamically in both directions.

4. Click the swap button in the center to reverse the conversion direction, or click the copy icon to copy the values to your clipboard.

💡 Pro Tip: Click any of the popular conversions at the bottom of the card to configure the fields instantly!

About Energy Converter

Energy is defined in physics as the capacity to do work. The standard International System of Units (SI) measurement for energy is the Joule (J), but depending on the industry—be it nutrition, electricity, or HVAC—you will encounter a vast array of different energy units.

Industry-Specific Energy Scales

Nutritionists and food scientists use the Calorie (specifically the kilocalorie or kcal) to measure the metabolic energy stored in food. The power and utilities industry relies heavily on Kilowatt-hours (kWh) for electricity billing, while the HVAC industry measures heating and cooling capacity using British Thermal Units (BTUs). For quantum physicists studying subatomic particles, the Electronvolt (eV) is the standard measurement.

Common Use Cases

Electricity Billing: Utility companies charge per Kilowatt-hour (kWh). Converting the wattage of a home appliance into kWh helps estimate monthly electricity costs.
Air Conditioning (HVAC): A room's size dictates the cooling power needed, measured in BTUs. A 10,000 BTU air conditioner removes roughly 2.93 kWh of heat per hour.
Diet and Nutrition: People tracking their diet often need to convert between Joules (common on European food labels) and Calories (common in the US).

Frequently Asked Questions

Learn more about energy converter and formulas

📚 5 Questions Answered

In nutritional contexts, a 'Calorie' (with a capital C) is actually a kilocalorie (1,000 small calories). This means when you read 200 Calories on a food label in the US, it technically contains 200,000 small, thermodynamic calories.

A Kilowatt-hour is a measure of electrical energy equivalent to a power consumption of 1,000 watts sustained for 1 hour. It is the standard unit utility companies use to bill for electricity.

One small calorie is equivalent to approximately 4.184 Joules. Because food labels use Kilocalories (kcal), one nutritional Calorie actually equals 4,184 Joules, or 4.184 Kilojoules (kJ).

BTU stands for British Thermal Unit. It is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. It is heavily used in the US for rating air conditioners and heaters.

A Watt is a unit of power, while a Joule is a unit of energy. The relationship is simple: 1 Watt equals 1 Joule of energy transferred per second. Therefore, running a 60-Watt lightbulb for one second consumes exactly 60 Joules of energy.