You have photographed the gas meter and can find the read numbers on the bill. Yet the billed consumption figure appears much higher. Before you conclude there has been excess consumption, check the units: this article performs a calculation for a customer gas supply contract. The result is a recalculated energy amount or a precisely located data gap.
Understanding the two quantities
According to the Bundesnetzagentur the gas meter measures volume in cubic metres. The bill uses kilowatt hours. The conversion is as follows:
Consumption in m³ × correction factor (Zustandszahl) × billing calorific value in kWh/m³ = energy in kWh. [BNETZA]
The calorific value (Brennwert) describes the energy content of the gas. The correction factor (Zustandszahl) takes into account the different volume states, among other things due to temperature and pressure. Both quantities are part of the conversion; a blanket factor from someone else’s example calculation does not replace the values on your bill. [BNETZA]
Select a specific billing line
Our editorial recommendation: start with a completed section for which the initial reading, final reading and both factors are present. Transfer device identifier, date boundaries and units unchanged. Note whether the document states a meter reading or another method of determination. The Bundesnetzagentur explicitly recommends checking the meter assignment, readings and method of determination when reviewing bills. [BNETZA]
Calculate a difference only between readings that belong together for the same device. If there was a change you need the separate measurement stretches; resolve this assignment before converting. Then look for the factors used for that specific billing section. If the assignment is missing, it remains unresolved. The spreadsheet should not be made to look complete by convenient guesses.
An example you can practise with one section
All numbers below are fictitious. They neither represent a typical consumption nor values for your connection.
- Initial reading: 15.340 m³
- Final reading: 15.840 m³
- Difference: 500 m³
- Correction factor (Zustandszahl): 0,96
- Billing calorific value (Abrechnungsbrennwert): 11,2 kWh/m³
The bill yields 500 × 0,96 × 11,2 = 5.376 kWh. The figure 5.376 is therefore not comparable to the 500 m³ as a like-for-like quantity. A direct numerical comparison here would ignore differing units.
Someone who instead uses a self-chosen factor of 10 gets 5.000 kWh. The difference of 376 kWh in this practice case arises solely from this substituted calculation approach. It does not demonstrate an error in the actual bill or an incorrect meter measurement. First compare the initial values and factors used.
Two sections already stated separately
A second, independent practice case likewise contains a total of 500 m³. However, the document explicitly assigns the volumes and factors to two sections:
- A – Consumption: 200 m³; correction factor (Zustandszahl): 0,96; calorific value: 11,0 kWh/m³; calculation result: 2.112 kWh
- B – Consumption: 300 m³; correction factor (Zustandszahl): 0,96; calorific value: 11,2 kWh/m³; calculation result: 3.225,6 kWh
- Total – Consumption: 500 m³; correction factor: —; calorific value: —; calculation result: 5.337,6 kWh
Calculate each stated line with its own data and add the energy amounts only afterwards. If you were to calculate the entire 500 m³ with the factors from B, you would get 5.376 kWh: 38,4 kWh more than the two individual calculations combined. Translating a section factor to the same total volume in m³ is therefore not mathematically correct.
The practice case takes the section volumes as given. It does not invent an intermediate reading nor distribute an annual consumption evenly across months. It also does not explain the technical procedure for deriving a billing calorific value from individual measurement data.
Document the first deviating calculation step
Compare your results line by line with the bill. Does the discrepancy already begin at the meter difference, at an adopted factor, only at the product, or at the addition of the sections? Record the first point of discrepancy with the original value, your own calculation and the corresponding page. Small differences are not judged as errors without knowledge of the used precision or rounding.
If a factor is missing or its period is unclear, ask for the actually applied value and its assignment. If the product is different with the same input values, present precisely that calculation line for clarification. The Bundesnetzagentur names the supplier or network operator as contacts for questions about calorific value and correction factor. [BNETZA]
A matching conversion only confirms that calculation step. It does not determine whether the meter measures correctly, whether the consumption was correctly determined, or whether the prices and other bill items are correct. Payments on account and euro amounts belong in a separate cost calculation afterwards. With your check you can now state concretely which kWh value follows from the stated data and which explanation may still be missing.