Gas Rate Calculator
Free tool from FC Training Academy. Work out heat input from a meter test and check it against the data plate.
Gas Rate Test Timer
Test duration
Take the start reading, press Start, and take the end reading when the alarm sounds.
Calculate Gas Heat Input
Enter the appliance's rated net heat input to check tolerance
Using CV: 38.76 MJ/m³ | Ratio: 1.11
Net heat input (rated 18 kW)
17.46 kW
Volume (m³)
0.0600
Flow (m³/h)
1.80
Gross kW
19.38
Data plate comparison
Within tolerance (-3.0%)Natural gas CV 38.76 MJ/m³ / 1040 Btu/ft³, ratio 1.11. LPG CV 93.2 MJ/m³ / 2500 Btu/ft³, ratio 1.09. For guidance only — always refer to current Gas Safe technical standards.
Combustion Ratio Check (CO/CO₂)
Enter the flue gas analyser readings and the ratio limit from the manufacturer's instructions (MI).
CO/CO₂ ratio
0.0009
Ratio = CO ÷ (CO₂ × 10,000). Always refer to the appliance manufacturer's instructions for the applicable limit.
Recent Gas Rate Calculations
No saved calculations yet. Run a calculation above and press "Save this result".
Tolerance shown is the common +5% / -10% of the rated net input. Always follow the manufacturer's instructions for the appliance.
View our gas coursesFor training and reference only. Check every result against the current standard, the manufacturer's instructions and your own readings. The engineer carrying out the work is responsible for the result.
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References to IGEM, British Standards, the Gas Safety (Installation and Use) Regulations and the LCL Awards Gas Safety Training Manual are for study only. Those documents remain the copyright of their owners and are not reproduced here.