Skip to tool

Energy Unit Converter

Convert joules, watt-hours, and kilowatt-hours in one step.

How to Use This Tool

  1. Type value and unit.
  2. Convert.
  3. Copy any line you need.

Learn More About Energy Unit Converter

Energy vs power

  • Energy (this tool) is stored or delivered work: joules or watt-hours.
  • Power is energy per time (watts). Use the Power Converter for W, kW, hp.

1 Wh = 3600 J exactly.

About

Convert energy between joules (J), kilojoules, megajoules, watt-hours (Wh), and kilowatt-hours (kWh). Useful for electricity bills, battery specs, and physics problems. Math comes from the convert package.

Examples

One kilowatt-hour

Utility-style kWh expressed in joules and related units.
Input
1 kWh
Output
J: 3600000.000000
kJ: 3600.000000
MJ: 3.600000
Wh: 1000.000000
kWh: 1.000000

3,600 joules

Exactly one watt-hour from joules.
Input
3600 J
Output
J: 3600.000000
kJ: 3.600000
MJ: 0.003600
Wh: 1.000000
kWh: 0.001000

Use Cases

  • Relating kWh on a utility bill to joules
  • Sizing battery energy in Wh vs MJ
  • Homework and lab unit checks

Frequently Asked Questions