Joules to kWh Converter

Convert energy between Joules (J) and kilowatt-hours (kWh) using the exact physical relationship.

Energy converter – Joules <→ kWh

Exact definition: 1 kWh = 3,600,000 J.

J
kWh

Joules and kilowatt-hours: the relationship

Joule (J) is the SI unit of energy, while kilowatt-hour (kWh) is a practical unit widely used for electricity billing and energy metering.

Core formulas

1 kWh = 1000 W × 3600 s = 3,600,000 J

kWh = J / 3,600,000

J = kWh × 3,600,000

Example: 500,000 J to kWh

kWh = 500,000 ÷ 3,600,000 ≈ 0.1389 kWh

Typical applications

  • Converting simulated or measured energy (in J) to kWh for cost estimates.
  • Checking laboratory calorimetry results against electrical energy usage.
  • Comparing energy from batteries, solar panels and grid electricity.

FAQ

Is this converter exact?

Yes. It uses the exact relationship 1 kWh = 3.6 × 106 J, with floating-point arithmetic. Small rounding differences may occur only due to display formatting.

Can I use it for very small or very large values?

Yes. Results are formatted in fixed or scientific notation depending on magnitude, so you can work from micro-scale Joules up to MWh-scale energies.

What about watt-hours (Wh)?

1 kWh = 1000 Wh and 1 Wh = 3600 J. If you prefer, you can mentally convert kWh to Wh and then to J, but this calculator handles the entire chain directly.