EU Energy Unit Converter & Electricity / Gas Bill Estimator

Converting kWh, MWh, m³ of gas, therms and GJ: the factors

Every conversion goes through the kWh: 1 MWh = 1,000 kWh, 1 GJ = 277.778 kWh, 1 thermie = 1.163 kWh, 1 BTU = 0.000293 kWh and 1 m³ of natural gas ≈ 11.2 kWh (gross calorific value), an adjustable factor. A yearly consumption of 4,500 kWh is therefore 4.5 MWh, 16.2 GJ or about 402 m³ of gas.

Factors used

Worked example

4,500 kWh = 4.5 MWh = 16.20 GJ = 3,869.3 thermies = 401.8 m³ of gas at 11.2 kWh/m³. Conversely, 1,000 m³ of gas gives 11,200 kWh.

The bill estimate

Yearly budget = kWh × price per kWh + standing charge, both entered including VAT (the tool adds no VAT), then ÷ 12 for the monthly amount. With 4,500 kWh at €0.25 and a €150 standing charge: 1,125 + 150 = €1,275 a year, €106.25 a month. The consumption part (€1,125) is split into 55% supply, 25% network and 20% taxes: a flat split, indicative and not verified.

Limits

• The price per kWh and the standing charge are entered including VAT: the tool adds no VAT. If your tariff shows prices before tax, add the VAT first.
• The gas factor varies with the distribution area and altitude; use the one on your bill (often between 10 and 12 kWh/m³).
• The €0.25/kWh starting price is not dated. For electricity in France, the regulated Base rate (6 kVA) is 13.61 c€/kWh excl. tax on 1 August 2026, i.e. €0.2003/kWh with excise and VAT.

Sources and dates: CRE decision 2026-147, annex B (rates on 01/08/2026); electricity excise €30.85/MWh from 01/02/2026 (BOFiP, BOI-RES-EAT-000240) (checked 14/10/2026)

Frequently Asked Questions

How many kWh are in one m³ of natural gas?

About 11.2 kWh (gross calorific value) per m³ with the tool's default factor. The exact factor depends on the area and is printed on your bill: 1,000 m³ gives 11,200 kWh at 11.2.

How do I convert GJ to kWh?

1 GJ equals 277.778 kWh, and 1 MWh equals 3.6 GJ. A consumption of 4,500 kWh is therefore 16.2 GJ.

What is a thermie?

An old French heat unit equal to 1 million calories, i.e. 1.163 kWh. 4,500 kWh is about 3,869 thermies. It differs from the British therm, which is about 29.3 kWh.

Should the price entered include VAT?

Yes. The field is labelled "incl. tax" and the tool adds no VAT: 4,500 kWh at €0.25 with a €150 standing charge give €1,275 a year, or €106.25 a month. If your tariff shows prices before tax, add the VAT first.

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.