Gas Pipe Sizing Calculator
Size common natural gas Schedule 40 metallic pipe sections using the Longest Length Method from entered run length and section BTU load.
This calculator is part of the HVACTools.pro free calculator collection, built for working HVAC technicians. The interactive widget loads when the page hydrates; the content below previews related tools while it loads.
Frequently asked questions
What is the longest length method for gas pipe sizing?
The longest length method sizes each section of gas piping using the longest piping run from the point of delivery to the most remote outlet and the load on that section.
How do you convert BTU per hour to CFH for natural gas sizing?
A common field conversion is about 1 cubic foot per hour of natural gas for every 1,000 BTU per hour.
Does this calculator size the whole system or one section?
This calculator is intended to size one pipe section at a time using the section load and the system's longest run length.
Does this replace the full fuel gas code tables?
No. This is a simplified field sizing aid. Final sizing still depends on gas type, pressure conditions, adopted code tables, local amendments, and actual installation requirements.
Related calculators
Browse all HVAC calculators · Troubleshooting workflows · HVAC guides · Tool reviews