Kilojoules to Kilowatt-hours Converter

kWh

Common Conversions

kJ	kWh
1	0.000278
10	0.00278
100	0.0278
1000	0.278
3600	1
5000	1.389
10000	2.778
36000	10
100000	27.78
360000	100
1000000	277.8

Why this conversion matters in chemistry

Process heat-balance simulation outputs run in kJ/hr; the plant energy-management system logs in kWh. A 36,000 kJ/hr reboiler duty is exactly 10 kWh/hr, the figure rolled up to a plant-wide energy KPI dashboard. The conversion is also the routine first step in any electrolysis-energy or thermal-cost calculation. Decomposing 1 mol of water needs 285.8 kJ, equivalent to 0.0794 kWh — for 1 kg of H₂, about 39.4 kWh, the lower-bound electrical-energy cost any green-hydrogen feasibility analysis works against.

Formula

kWh = kJ ÷ 3600

Worked Examples

3600 kJ = 1 kWh

The conversion anchor — exactly one kilowatt-hour.

1000 kJ = 0.2778 kWh

1 MJ — about 0.278 kWh, useful as a quick mental factor.

100 kJ = 0.0278 kWh

100 kJ — about a moderate reaction enthalpy in kWh form.

36000 kJ = 10 kWh

10 kWh — about a typical industrial heater hourly duty in electrical-energy terms.

Frequently Asked Questions

How do I convert kJ to kWh?

Divide by 3600. So 3600 kJ becomes exactly 1 kWh. The factor is exact through 1 kWh = 1 kW × 3600 s = 3.6 × 10⁶ J.

Why convert reaction energies to kWh?

Electricity-cost estimation. A 1000 kJ heating requirement at $0.10/kWh costs about 2.8 cents — small per reaction, but the same conversion scaled to a manufacturing run sets the energy bill.

What's 1 MJ in kWh?

Exactly 0.2778 kWh. The mental anchor 3.6 MJ ≈ 1 kWh is exact and useful for any quick energy-cost estimate.

How much energy does water electrolysis need?

Decomposing 1 mol of liquid water at 25 °C needs 285.8 kJ (ΔH for the reaction H₂O → H₂ + ½O₂), equivalent to 0.0794 kWh. Scaling to 1 kg of H₂ gives about 39.4 kWh — the thermodynamic floor for green-hydrogen production.