Gas Line Pressure Drop Calculator

Gas has to travel, and every foot of pipe and every elbow bleeds pressure. When the appliance at the far end gets less than it needs, the flame is the symptom - the drop is the cause.

Gas Line Pressure Drop Calculator estimates the drop along a run in inches water column and psi.

• Flow driven: Enter CFH of gas.
• Fittings: Equivalent length built in.
• Fuel aware: NG or propane gravity.
• Dual units: In w.c. and psi.
• Live update: Results while you type.
• Export: Text, CSV or JSON report.

1. Enter gas flow in CFH.
2. Pick the pipe size and enter length.
3. Choose the fuel and fitting allowance.
4. Read the pressure drop in in w.c. and psi.
5. Export the result if needed.

Example 1. 100 CFH of natural gas through 50 ft of 1-inch pipe drops under 0.1 in w.c. - no concern.

Example 2. Push the same flow through 3/4-inch pipe and the drop climbs past 0.4 in w.c.; over a long run that is the difference between working and starving appliances.

• Friction correct: Darcy-Weisbach approach.
• Fittings: Equivalent length added.
• Dual units: In w.c. and psi.
• Free and private: No uploads, no logging.