# Energy Converter

> Convert between joule, kilojoule, calorie, kilocalorie, watt-hour, kilowatt-hour, BTU, electron-volt, and more.

URL: https://uttir.com/energy-converter
Categories: converters, math-tools
Privacy: Conversions run locally in your browser. No values are sent anywhere.

## About

Energy shows up in many units depending on the field: joules in physics, kilowatt-hours on utility bills, calories in nutrition, BTU in heating and cooling, and electron-volts in atomic physics. They are all measuring the same thing; the units just differ by a power of 10 (and sometimes by definition, like food calories vs thermochemical calories).

This converter uses the joule as the base. The math is local.

## How to use

1. **Enter a value** — Type the energy in any supported unit. The default is 1 kWh.
2. **Pick the units** — The from/to dropdowns list all supported units. Result updates live.
3. **Watch the quick-reference table** — For 1, 10, 100, 1000, 10000 in the source unit, the table shows the equivalent in the target.

## Examples

### 1 kWh = how many joules?

One kilowatt-hour is 3.6 megajoules.

Input:

```
1 kWh
```

Output:

```
= 3,600,000 J (3.6 MJ)
```

## FAQ

### How many joules is 1 food Calorie?

1 food Calorie (1 kcal) = 4,184 J. Food labels in the US use kcal but write "Calories" with a capital C.

### How many BTU does it take to heat a house?

A typical US home uses about 50,000-100,000 BTU per day in winter (from the furnace).

### Why are BTU and kWh different magnitudes?

BTU is older (steam-engine era); kWh is the modern unit. 1 kWh ≈ 3,412 BTU. Most US heating systems still quote BTU/h (BTU per hour) for power rating, while utility bills use kWh for energy.

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- [Pressure Converter](https://uttir.com/pressure-converter) — Convert between pascal, bar, psi, atmosphere, mmHg, torr, and other pressure units instantly.
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- [Compound Interest Calculator](https://uttir.com/compound-interest-calculator) — Project savings growth with compound interest and monthly contributions, year by year.

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For the full HTML page with the live tool, visit https://uttir.com/energy-converter.
This file is the markdown rendering at https://uttir.com/energy-converter.md. See https://uttir.com/llms.txt for a site-wide summary.