Gas Rate Calculator

This page contains gas rate calculators used for working out gas consumption of appliances and to make sure they are within manufacturers and gas safety tolerances. 

Shown below are:- 

  • Gas Rate Calculator for Imperial with Fuel Type Natural Gas
  • Gas Rate Calculator for Metric with Fuel Type of Natural Gas.
  • Instructions for appliances with Imperial Meters
  • Instructions for appliance with Metric Meters
  • Gas Rate Chart for Imperial gas rating
  • Gas Rate Chart for Metric meter rating

Additional notes: In ‘Imperial’ mode, you may currently have timing for upto 180 seconds using the slider. In ‘Metric’ mode you can adjust the timer between 1 and 120 seconds.

For full instructions on how to carry out the test, see below the calculators.

Heat Input Instructions for an Appliance – Imperial

  1. Ensure that all other gas burning appliances are turned off
  2. Turn on the applinace to be rated to its maximum setting – allow to run for 10 minutes
  3. Time in seconds how long it takes for test dial to complete 1 revolution (1ft3)

  • ft3 x 0.028 = m3

  1. Appliance Input (kW) = (3600/t) x 0.028 x (CV/3.6)
    • t – time in seconds per 1 revolution
    • 0.028 – to convert ft3into m3
    • CV – calorific value of natural gas 38.76MJ/m3 (1040 BTUs)
    • 3.6 – converts Mj into kW
  2. Appliance Input (kW) = (3600/t) x 1040/3412

Heat Input Instructions for an Appliance – Metric

  1. Ensure that all other gas burning appliances are turned off
  2. Turn on the applinace to be rated to its maximum setting – allow to run for 10 minutes
  3. Take the first reading from the meter R1
  4. At exactly 2 minutes take the second reading R2
  • Appliance Input (kW) = Gas Rate ((R2-R1) x 30min) x CV(kW)
    • R1 – first reading of the meter
    • R2 – second reading after 2min
    • CV – calorific value 10.77 kW

If you would like access to a full gas rating chart for metric gas meters upto 0.200 units then please go to Gas Rating Chart Metric

If you would like access to a full gas rating chart for imperial gas meters upto 200 seconds then please go to Gas Rating Chart Imperial

Thank you for visiting this page, we hope you like the calculators. If there are any improvements to be made, please feel free to call us or send us a message. We can make changes very quickly. Feel free to drop us a whatsapp or text message on +447484 842790

Disclaimer: Information on this website is provided for informational purpose therefore we cannot accept liability for subsequent problems. All repair tasks should be carried out by qualified trades people. We may also receive commission payments when you are taken to external websites and complete purchases from third party sellers, once you leave our site, we cannot be held liable for your purchases.