This is the feature packed Gas Rate Calculator & Guide, from Mr Combi Training!

We've managed to cram all of this into one app....

• Metric and imperial gas rate calculators
• Save, email or export your results to other apps such as Dropbox, Google Drive or Evernote
• Built-in torch
• Tightness and let-by timer
• Conversion calculator
• Full gas rate guide
• Supports natural gas, butane and propane
• Save manual calorific values for improved accuracy
• Select between a 1 and 2 minute timer for metric meters
• Selectable timer alert
• Supports ¼ft³, ½ft³ 1ft³, 2ft³ and 5ft³ imperial test dials

A guide has been built into the app with 6 pages:
• Metric gas rate calculations
• Imperial gas rate calculations
• Heat input calculations
• Let-by test procedure
• Tightness test procedure
• Permissible drops on the tightness test

An extra Converter calculator is included in the app for simple conversions between gas rates and heat inputs. Simply select the type of gas, enter a value, select the units, press the 'Calculate' button and the calculator will show all gas rates (cubic metres per hour, cubic feet per hour and litres per second) and heat inputs (MJ/h, kW and BTUs per hour) based on the CV.

The Tightness Testing function allows you to quickly select between the let-by and tightness tests and has an easy to use timer. No longer do you need to fiddle about with your phone's timer!

Calorific values can be entered manually (and saved) for more accurate gas rate calculation results. The calorific value of natural gas in the UK varies from about 38.3 to 40.5 MJ per cubic metre; this can mean a difference in the gas rate calculation of more than 5%! With this calculator you can add the CV for your area in the settings page and avoid these inaccuracies. The default values set for butane and propane are both the same as supplied by Calor and BOC.

The metric timer can be set to either 1 or 2 minutes. For U6 and G4 meters one minute is sufficient, for E6 meters two minutes is recommended for accuracy. The timer can be set to an audible alert, vibrate, both or neither.

A torch function is included with this app if your device has an LED flash.

What’s New

Version 2.4

We've made some small tweaks for iOS 12.

Ratings and Reviews

4.4 out of 5
7 Ratings

7 Ratings

d-jay ,

My go to app

Having dropped from industrial gas back to commercial gas and tried most apps here this is my go to app for gas rates.
With the ability to save so I have proof always at hand should I ever need it.
Well worth the price and surprised not many reviews.

Freddie de gas man ,


I'm surprised that this app hasn't got any review yet. I've tried all the free ones but they are rubbish with so many annoying ads. This one is not free but definitely worth it. I'm well pleased.

b0schboy ,

Great apps

Great apps stops me worrying about ACS


Mr Combi Sales Ltd.
2 MB

Requires iOS 8.0 or later. Compatible with iPhone, iPad and iPod touch.



Age Rating


  • Family Sharing

    Up to six family members will be able to use this app with Family Sharing enabled.

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