Gas Pipe Sizing Calculator

About the Gas Pipe Sizing Calculator

Estimates whether a gas pipe size can carry a required BTU load over a given length, using a simplified longest-length capacity approach.

How to use this calculator

1. Enter the total gas load in BTU per hour for the appliances you want to serve.
2. Enter the pipe length, usually the run from the meter or regulator to the farthest appliance.
3. Choose the pipe material or size options shown by the calculator, if applicable.
4. Read the estimated capacity and compare it to your required load.

The formula explained

This calculator estimates gas pipe capacity from the appliance load and the run length, then compares that demand to a practical capacity estimate. In simple terms, it helps you see whether a pipe size is likely to handle the BTU load over the distance you entered.

• BTU = the heating load or gas demand of the connected appliances, measured in BTU per hour
• L = the pipe length or run distance
• C = the estimated capacity of the pipe
• d = the pipe diameter or size, if the calculator includes pipe size options

Step by step method

1. Add up the BTU per hour ratings of all appliances on the line.
2. Measure the pipe run length from the source to the farthest appliance.
3. Enter those values into the calculator and select the pipe type or size if needed.
4. Check whether the estimated capacity is greater than or equal to the total BTU load.

Worked example

Problem. A home has two appliances on one gas line, one uses 40,000 BTU/h and the other uses 25,000 BTU/h. The pipe run is 60 ft. Can the line likely handle the load?

1. First, add the loads: 40,000 + 25,000 = 65,000 BTU/h.
2. Next, enter 65,000 for the load and 60 for the length.
3. If the calculator shows a capacity above 65,000 BTU/h, the pipe size is likely adequate for that run.

Tips and common mistakes

• Use the farthest appliance in the run, because length affects pressure drop.
• Always total all connected appliance loads, not just the largest one.

Frequently asked questions