What does the Energy Converter work out?

Convert joules, calories, kWh, BTU and food calories. It is one of the Unit Converters tools on Mondo Knows.

Do I need to sign up, and is my data stored?

No sign-up, and nothing you type is sent anywhere. The calculation runs in your own browser, so the figures stay on your device and the page works offline once loaded.

Mondo Knows Tools

Energy Converter

Convert joules, calories, kWh, BTU and food calories. Use the free energy converter below to get an instant answer, with the formula shown so you can check the maths and trust the result. Free, private, and no sign-up.

Value

Unit you have

Unit for the big answer

Mondo says

1 kWh =

860.421

kcal

Joule (J)3,600,000

Kilojoule (kJ)3,600

Megajoule (MJ)3.6

Calorie (small) (cal)860,421

Food calorie (large) (kcal)860.421

Watt-hour (Wh)1,000

Kilowatt-hour (kWh)1

British thermal unit (BTU)3,412.14

Therm (thm)0.0341214

Foot-pound (ft·lb)2,655,220

Electronvolt (eV)2.2469e+25

11 units. The bold row is the unit you picked for the big answer.

How it works

Energy units are a minefield because a food Calorie is a thousand physics calories, and a kilowatt-hour is 3.6 million joules. This page spells out the difference instead of quietly dropping a factor of a thousand.

The formula

Every unit is defined by how many base units it is worth, so the conversion is value x factor(from) / factor(to).

Energy Converter: common questions

What does the Energy Converter work out?: Convert joules, calories, kWh, BTU and food calories. It is one of the Unit Converters tools on Mondo Knows.
How is the Energy Converter calculated?: Energy units are a minefield because a food Calorie is a thousand physics calories, and a kilowatt-hour is 3.6 million joules. This page spells out the difference instead of quietly dropping a factor of a thousand. The maths is short enough to check by hand: Every unit is defined by how many base units it is worth, so the conversion is value x factor(from) / factor(to).
Do I need to sign up, and is my data stored?: No sign-up, and nothing you type is sent anywhere. The calculation runs in your own browser, so the figures stay on your device and the page works offline once loaded.

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Estimates for general guidance only. This is not financial, medical or legal advice. Everything runs in your browser and nothing you type is stored.