Is the Energy Converter free to use?

Yes, the Energy Converter is completely free. No account, subscription, or signup is required — ever.

Does my data get uploaded anywhere?

No. The Energy Converter runs entirely in your browser. Your data is never sent to any server.

Does it work offline?

Yes. Once the page has loaded, the tool works without an internet connection.

Which browsers are supported?

All modern browsers — Chrome, Firefox, Safari, and Edge. No plugins or extensions required.

What is 1 food calorie in joules?

1 food calorie (kilocalorie, kcal) = 4,184 J = 4.184 kJ. Food labels typically list kcal, not cal.

Energy Converter

Convert between joules, calories, kilowatt-hours, BTU, and more.

From

Joule (J)

0.001

Kilojoule (kJ)

1 J = 0.001 kJ

All Conversions for 1 J

Kilojoule	kJ	0.001
Megajoule	MJ	0.000001
Calorie	cal	0.2390057361
Kilocalorie (kcal)	kcal	0.0002390057361
Watt-hour	Wh	0.0002777777778
Kilowatt-hour	kWh	2.777778e-7
Electronvolt	eV	6.241496e+18
BTU	BTU	0.0009478133945
Foot-pound	ft·lb	0.7375610332

What is the Free Energy Converter?

The free Energy Converter covers 10 units: joules (J), kilojoules (kJ), megajoules (MJ), calories (cal), kilocalories (kcal), watt-hours (Wh), kilowatt-hours (kWh), electron volts (eV), British Thermal Units (BTU), and foot-pounds (ft·lb). Enter an energy value, select source and target units, and convert instantly. The All Conversions table displays all 10 units at once for scientific, nutritional, and engineering reference.

→ Converting kcal to kJ for international nutrition label reading
→ Converting kWh to MJ for energy billing or solar panel output
→ Converting BTU to kJ for HVAC system specifications
→ Converting joules to eV for particle physics or semiconductor work

How to Use the Free Energy Converter

1 Select the source energy unit (e.g. kcal) from the From dropdown.
2 Enter the energy value in the input field.
3 Choose the target unit (e.g. kJ) from the To dropdown.
4 View the instant conversion result.
5 Click ⇄ Swap to reverse direction.
6 See every unit in the All Conversions table.

Key Features

⚡
10 energy units

Spans nutrition (cal, kcal), electrical (Wh, kWh), physics (J, eV), and engineering (BTU, ft·lb).
🍎
Nutrition and food science

Convert food calories (kcal) to kJ for international nutrition label comparison.
🔋
Electrical energy

Wh and kWh support for battery, solar panel, and energy billing calculations.
📊
All Conversions table

Full-spectrum view of all 10 energy units at once.
🆓
Free, no registration

Works entirely in-browser with no account required.

Example Usage

Example Input

From: kcal · Value: 2000 · To: kJ

Example Output

2000 kcal = 8,368 kJ

Frequently Asked Questions about the Free Energy Converter

What is the free Energy Converter?: Convert between joules, calories, kilowatt-hours, BTU, and more.
Is the Energy Converter free to use?: Yes, the Energy Converter is completely free. No account, subscription, or signup is required — ever.
Does my data get uploaded anywhere?: No. The Energy Converter runs entirely in your browser. Your data is never sent to any server.
Does it work offline?: Yes. Once the page has loaded, the tool works without an internet connection.
Which browsers are supported?: All modern browsers — Chrome, Firefox, Safari, and Edge. No plugins or extensions required.
What is 1 food calorie in joules?: 1 food calorie (kilocalorie, kcal) = 4,184 J = 4.184 kJ. Food labels typically list kcal, not cal.