Work out gas appliance load instantly with clear inputs, formula shown and shareable results.
Fuel gas systems are sized on total connected load, not on expected simultaneous use, because any appliance may fire at any time. The sum in BTU per hour divided by 1030 gives cubic feet per hour, and meters are specified with about 25 percent headroom so future appliances do not force a service upgrade.
Connected load
Total BTU/h = sum of all appliance input ratings; ft³/h = total / 1030
Meter sizing
Meter ft³/h = demand x 1.25, rounded up to the next catalogue capacity
Preliminary estimate only. Confirm connected load, meter capacity and service pressure with the gas utility and a licensed installer.
Total BTU/h = sum of all appliance input ratings; ft³/h = total / 1030. Fuel gas systems are sized on total connected load, not on expected simultaneous use, because any appliance may fire at any time.
Not for the piping. Gas codes require the full connected load for pipe sizing, although utilities may apply diversity when sizing the service main itself.
This calculator takes 4 inputs: Furnace or boiler input, Water heater input, Cooking appliance input, Other appliances. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.