Is a food Calorie the same as a kilocalorie?

Yes. The Calorie on a nutrition label (capital C) is one kilocalorie, 1,000 small calories or 4,184 joules. A 2,000 Calorie diet is about 8.4 megajoules.

How many joules are in a kilowatt-hour?

Exactly 3,600,000 joules (3.6 MJ), because a kilowatt-hour is 1,000 watts sustained for 3,600 seconds. It is also about 860 kilocalories or 3,412 BTU.

A British thermal unit is the energy needed to raise one pound of water by one degree Fahrenheit, defined here as 1,055.05585262 joules. It is still used for heating and air conditioning capacity, usually as BTU per hour.

What is an electronvolt used for?

An electronvolt is the energy an electron gains crossing one volt, exactly 1.602176634 × 10⁻¹⁹ joules. It is the natural unit for atomic physics, chemistry bond energies and particle accelerators, where joules would be absurdly small numbers.

Energy

Joules, calories, kilowatt-hours and BTU.

About Energy

Convert energy between joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, electronvolts and BTU. Every other unit is shown as you type.

How to use

Type a value and pick its unit. The default is 100 kilocalories.
Every other unit updates as you type; each row has its own Copy button, and Copy on the panel copies the whole table.
Results are rounded to eight decimal places and formatted for your locale.

Conversion factors

All units convert through joules:

Unit	Joules
calorie (thermochemical)	4.184
kilocalorie (food Calorie)	4 184
watt-hour	3 600
kilowatt-hour	3 600 000
BTU (International Table)	1 055.05585262
electronvolt	1.602176634 × 10⁻¹⁹

The calorie is the thermochemical calorie (exactly 4.184 J), and the BTU is the International Table British thermal unit. The value must be greater than zero.

Example

100 kcal → 418 400 J · 418.4 kJ · 116.22222222 Wh · 0.11622222 kWh · 396.56668314 BTU

Privacy

Runs in the browser. No request is made, and nothing is stored.

Frequently asked questions

Is a food Calorie the same as a kilocalorie?: Yes. The Calorie on a nutrition label (capital C) is one kilocalorie, 1,000 small calories or 4,184 joules. A 2,000 Calorie diet is about 8.4 megajoules.
How many joules are in a kilowatt-hour?: Exactly 3,600,000 joules (3.6 MJ), because a kilowatt-hour is 1,000 watts sustained for 3,600 seconds. It is also about 860 kilocalories or 3,412 BTU.
What is a BTU?: A British thermal unit is the energy needed to raise one pound of water by one degree Fahrenheit, defined here as 1,055.05585262 joules. It is still used for heating and air conditioning capacity, usually as BTU per hour.
What is an electronvolt used for?: An electronvolt is the energy an electron gains crossing one volt, exactly 1.602176634 × 10⁻¹⁹ joules. It is the natural unit for atomic physics, chemistry bond energies and particle accelerators, where joules would be absurdly small numbers.

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Reference

ASCII Table: Every ASCII character with its decimal, hex, octal, binary and HTML code.
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