Converting Gas Units to kWh

If your business receives gas bills from Energies Direct or another supplier, you’ll notice that your gas meter measures consumption in units of volume (either cubic metres or cubic feet). However, energy costs are billed in kilowatt-hours (kWh) — the universal measure of energy used for both gas and electricity.

This guide explains how to convert your gas usage into kWh, so you can better understand, verify, and manage your business energy costs.

Why Businesses Should Convert Gas Units to kWh

Understanding how to convert gas usage helps your business:

  • Verify your bills: Ensure that your invoiced kWh aligns with your actual meter readings.
  • Control energy costs: Knowing your true usage helps you identify efficiency opportunities.
  • Simplify energy reporting: kWh provides a single standard unit for tracking gas and electricity together.
  • Compare tariffs easily: Gas and electricity prices are both quoted in pence per kWh, enabling clearer cost comparison.

Step 1: Identify Your Gas Meter Type

Before converting, check which type of gas meter your business uses:

Meter TypeUnits DisplayedCommon inExample Reading
Metric meterCubic metres (m³)Modern installations00456.789
Imperial meterCubic feet (ft³) or hundreds of cubic feet (hcf)Older installations01234

The conversion process is the same in principle but uses slightly different factors depending on the meter units.

Step 2: Use the Correct Conversion Formula

For Metric Meters (m³)

kWh = Volume (m³) × Calorific Value × Correction Factor ÷ 3.6

Typical business values:

  • Calorific Value (CV): 38.0 – 40.0 MJ/m³
  • Correction Factor: ~1.02264
  • 3.6 is the constant to convert megajoules to kilowatt-hours

Example (metric): If your business used 250 m³ with a CV of 39.5 MJ/m³:

250 × 39.5 × 1.02264 ÷ 3.6 = 2,804.3 kWh

Result: 2,804.3 kWh

For Imperial Meters (ft³)

If your meter reads in cubic feet, first convert to cubic metres, then apply the same formula.

Volume (m³) = Cubic feet used × 0.0283

kWh = (ft³ used × 0.0283) × CV × Correction Factor ÷ 3.6

Example (imperial): If your business used 900 ft³ with a CV of 39 MJ/m³:

900 × 0.0283 × 39 × 1.02264 ÷ 3.6 ≈ 280.2 kWh

Result: ≈ 280.2 kWh

Tip: Business invoices often show the calorific value and correction factor used — compare those to your meter readings to confirm accuracy.

Step 3: Understand Each Factor

TermDescriptionTypical Value
Calorific ValueMeasures the energy content of the gas. It varies depending on gas quality and supplier region.38–40 MJ/m³
Correction FactorAdjusts for gas temperature and pressure conditions.1.02264
3.6Converts from megajoules to kilowatt-hours.Fixed constant

Your supplier includes the exact values on your gas bill for full transparency.

Example Business Calculation
InputValue
Meter TypeMetric
Usage1,100 m³
Calorific Value39.6 MJ/m³
Correction Factor1.02264
1,100 × 39.6 × 1.02264 ÷ 3.6 = 12,362 kWh
Result: Your business used approximately 12,362 kWh of gas in the billing period.

Common Questions

Does my business need to do this manually?

Usually, your supplier performs the conversion automatically on your bill. However, checking it yourself ensures accuracy — especially for multi-site businesses or where consumption monitoring is important.

What if my gas is charged differently?

All UK business gas tariffs are based on kWh, so even if your meter shows cubic metres, your charges will always relate to kWh.

How do I find my calorific value?

It’s printed on your gas bill. If not, you can use the Ofgem national average of 39.5 MJ/m³ as a reasonable estimate.

Why Energies Direct Simplifies Business Energy

At Energies Direct, we make energy management easier for businesses by providing:

  • Clear, itemised bills with kWh conversions shown transparently
  • Online tools to track and forecast energy use
  • Expert advice to help lower costs and reduce carbon emissions