Energy

Switch between energy units (J, kJ, kcal, Wh, kWh, BTU, eV, foot-pounds) in your browser. No upload, no signup, instant results.

Conversions

Output

0.001

Kilojoule

1 Joule → Kilojoule

How was your conversion?

Energy rating: 4.8 / 5.0 (25 reviews)

About Energy Converter

Energy Converter swaps between SI units (joules, kilojoules), dietary and thermodynamic calories (kcal and cal), electrical energy (watt-hours and kilowatt-hours), thermal units (BTU), tiny-scale electron-volts, and mechanical foot-pounds. Useful for nutrition labels that mix kcal and kJ, appliance spec sheets that quote kWh per year, and physics homework that switches between eV and J. All factors use full precision and the panel runs as a single static page in your browser — works offline, no signup, nothing uploaded.

Best for

  • Translating food labels between kcal and kJ across US and EU packaging
  • Appliance spec sheets that quote annual kWh — compare to your tariff
  • Physics homework touching eV, J, and foot-pounds in one problem

Pros

  • +J, kcal, Wh, BTU, eV, ft·lbf all in one panel
  • +Dietary and thermodynamic calories distinguished
  • +Local JavaScript only; no signup, no uploads, works offline

Cons

  • −Bomb calories (uppercase Cal) vs gram calories both read the same field
  • −No power-to-energy conversion — enter watt-hours directly

How to use Energy Converter

  1. 1

    Enter the source value, color code, or parameters in the input fields.

  2. 2

    Select the source and destination units or models from the option dropdowns.

  3. 3

    Watch the output update instantly in real-time as you type or adjust.

  4. 4

    Copy the converted results to your clipboard with a single click.

Frequently Asked Questions

What's the difference between a calorie and a kilocalorie?
Lowercase 'cal' is a gram calorie (the heat to warm 1 g of water 1 °C). Uppercase 'Cal' on food labels is a kilocalorie (1000 cal). The panel labels both fields, so don't accidentally divide a food label by 1000.
How many joules in a watt-hour?
1 watt-hour = 3600 joules. 1 kilowatt-hour = 3.6 million joules. The panel handles both conversions so your electric bill numbers map cleanly to SI energy.
Does it include BTU?
Yes — 1 BTU = 1055.06 J. HVAC and water-heater spec sheets quote BTU/hr; multiply by hours if you need energy in BTU rather than power.
Can I convert electron-volts for a subatomic problem?
Yes. 1 eV = 1.602e-19 J. Atomic and particle physics values use scientific notation by default since the numbers are tiny.
Are my energy inputs uploaded?
Never. Conversion runs as local JavaScript in your browser. Nutrition numbers, bill values, and physics homework never leave your device.

Related tools

FREE

100% Free

No hidden fees, no subscriptions, and no limits. Enjoy complete access to all features gratis.

SIGNUP

No Signup Required

Start converting immediately without creating an account or sharing email address.

PRIVACY

Private & Secure

Your files never leave your device. All processing is completed locally for maximum privacy.

BATCH

Batch Conversion

Convert multiple files simultaneously to save time. Fast and efficient multi-file queue.

LOCAL

Runs in Browser

Utilizes advanced client-side WebAssembly technology to process files directly inside your tab.

FORMATS

200+ Formats

Supports a wide variety of formats including images, documents, audio, video, and more.

USER REVIEWS

Energy Quality Rating

4.8
25 reviews

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