Energy Multi-Unit Converter (Joules, kWh, kcal, BTU

Energy is the capacity to perform work. Unit conversions bridge physics SI units (Joules), electrical units (kWh), dietary thermal units (kcal), and HVAC units (BTU).

To use the Energy Multi-Unit Converter (Joules, kWh, kcal, BTU), enter your Energy Value, Source Energy Unit. The calculator instantly computes Joules (J), Kilojoules (kJ) and more. Results update in real time as you change any input — no submit button needed.

How to Use This Calculator

Enter your Energy Value (e.g. 1000) and Source Energy Unit — choose from Joules (J), Kilojoules (kJ), Megajoules (MJ). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

1 kWh = 3,600,000 Joules = 3,600 kJ = 860.42 kcal = 3,412.14 BTU

1 kcal = 4,184 Joules = 4.184 kJ

1 BTU = 1,055.06 Joules = 0.252 kcal

Worked Example

Convert 1,000 Kilojoules (1,000 kJ):

1,000 kJ = 1,000,000 Joules = 0.27778 kWh = 239.01 kcal = 947.82 BTU = 737,562 ft·lbf.

Understanding Your Result

Energy unit conversions: 1 kWh = 3,600,000 J = 3,412 BTU. US residential electricity: average 10,500 kWh/year (875 kWh/month) at approximately 0.16/kWh average. Energy Star appliances use 10–50% less energy than standard models. Solar panel output: a 400W panel produces approximately 1.5 kWh/day in average US locations. Power (watts) is the rate of energy use; energy (kWh or joules) is the total consumption over time — a 1,000W (1 kW) device running 1 hour uses 1 kWh.