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Thermal Energy0.000Gcal
Equivalent in MWh:0.00
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About

Energy metering in industrial sectors often requires converting volumetric flow into thermal energy units. Natural gas meters typically measure volume in cubic meters (m3), while utility billing and boiler efficiency calculations are frequently conducted in Gigacalories (Gcal). The discrepancy between volume and energy content arises because the calorific value of natural gas is not constant; it fluctuates based on the chemical composition of the methane mixture, temperature, and pressure.

This tool performs the conversion by applying a specific calorific value factor. While the standard reference is often cited as 8000 kcal/m3, variations in supply can range from 7500 to 8500 kcal/m3. Precise conversion is critical for reconciling fuel costs with actual heat output in district heating systems and manufacturing plants.

gas conversion energy audit heating calculator m3 to gcal calorific value

Formulas

The conversion relies on the definition that one Gigacalorie is equal to 106 kilocalories. The formula multiplies the gas volume by the specific calorific value of the fuel source.

EGcal = Vm3 × Qkcal106

Where:

  • E is the Energy in Gigacalories.
  • V is the Volume in cubic meters.
  • Q is the Calorific Value (Heat of Combustion) in kcal/m3.

Reference Data

Gas Quality / TypeLow Heating Value (kcal/m3)High Heating Value (kcal/m3)Approx. Conversion (Gcal/1000m3)
Standard Natural Gas (Low)760084007.68.4
G20 (Pure Methane Reference)812790258.13
G25 (Dutch/Low Cal)699077606.99
Associated Petroleum Gas9000105009.010.5
Biogas (60% Methane)500055005.0
Propane (Gas Phase)210002300021.0
Butane (Gas Phase)280003000028.0
LNG (Regasified)920096009.29.6

Frequently Asked Questions

This is a widely accepted industrial average for pipeline natural gas. However, exact values depend on the mixture of methane, ethane, and inert gases. Check your supplier's invoice for the exact "Heat of Combustion" or "Calorific Value".
Both are units of energy. 1 Gcal is approximately 1.163 Megawatt-hours (MWh). Gcal is more common in district heating and legacy boiler systems, while MWh is standard for electricity and modern energy trading.
Yes. Gas volume changes with temperature (Charles's Law). This calculator assumes the input volume is already corrected to standard conditions (Standard Cubic Meters) or that the Calorific Value provided accounts for the operating conditions.
Yes, but you must change the Calorific Value significantly. LPG (Propane/Butane) has a much higher energy density per cubic meter of gas than natural gas (Methane).