Gas Pipe Sizing - NFPA 54

Gas Pipe Sizing Calculator helps you size natural gas and propane piping systems per the printed NFPA 54 (National Fuel Gas Code) / IFGC sizing tables. Instantly determine correct pipe diameter for black iron, CSST (corrugated stainless steel tubing), and semirigid copper piping based on BTU demand, inlet pressure, and pipe run length. Works for low-pressure, 2-psi, and 5-psi natural gas systems and low-pressure and 2-psi propane systems. Perfect for plumbers, gas fitters, and HVAC technicians. Works 100% offline on the job site.

FEATURES
• Dual Gas Support: Natural gas and propane (LP) each use their own printed NFPA 54 / IFGC capacity tables — no approximation multipliers
• 3 Pipe Materials: Black iron (Schedule 40), CSST (by EHD flow designation), and semirigid copper with material-specific printed tables
• Inlet Pressure Classes: Low pressure (<2 psi), 2 psi, and 5 psi for natural gas; low pressure (11" w.c.) and 2 psi for propane (the code has no printed 5-psi LP tables)
• Pipe Diameters: Black iron 1/2" through 4"; copper and CSST 1/2" through 2" (CSST capacities per conservative EHD for each nominal)
• 10 Length Brackets: Pipe runs from 10 feet to 200 feet, rounded up per code practice
• BTU Input: Enter appliance or total system demand in BTU/h
• Result Note: Shows the exact NFPA 54 / IFGC table used for every result

HOW IT WORKS
1. Select gas type (natural gas or propane)
2. Enter inlet pressure (low pressure, 2 psi, or 5 psi)
3. Input total BTU demand from gas appliances
4. Enter pipe material (black iron, CSST, or copper Type L)
5. Enter longest pipe run distance
6. See recommended pipe diameter with NFPA 54 capacity verification

PERFECT FOR
• Plumbers installing natural gas and propane systems
• Gas fitters and propane technicians
• HVAC technicians sizing gas furnace piping
• Plumbing contractors and estimators
• Mechanical engineers designing gas systems
• Plumbing inspectors verifying system compliance

OPTIONAL PRO UPGRADE — $2.99 ONE-TIME IN-APP PURCHASE
The following features require a separate one-time in-app purchase. They are not required to use the calculator:
• Unlimited saved calculation history
• PDF export of results
• Dark theme
• Ad-free experience

STANDARDS & COMPLIANCE
Capacities follow the printed NFPA 54 (National Fuel Gas Code) / IFGC Section 402.4 sizing tables: Schedule 40 steel (Tables 402.4(2)/(5)/(7) natural gas, 402.4(28)/(27) propane), semirigid copper (402.4(9)/(12)/(14) and 402.4(30)/(31)), and CSST by EHD (402.4(15)/(18)/(19) and 402.4(32)/(33)). Always confirm with your local code official and the tubing manufacturer table for CSST.

PERFECT FOR
• Plumbers and gas fitters
• HVAC technicians and contractors
• Propane technicians and installers
• Plumbing contractors and estimators
• Mechanical engineers
• Code officials and inspectors

OFFLINE & PRIVACY
• Works 100% offline - no internet needed for calculations
• No account required - instant access without signup
• No data collection - all calculations stored locally
• No tracking or cloud dependencies

Part of PlumbTools Suite - professional plumbing and HVAC calculator tools. Size gas systems faster, eliminate sizing errors, and ensure full NFPA 54 code compliance with accurate gas pipe sizing calculations.