Compressed Air Pipe Size Calculator
Pipe diameter for a compressed air line.
Enter your values
ⓘ Live results
Results
- Pressure drop
- 346.47 psi
- Verdict
- Too much — increase pipe size
- Minimum diameter for 2 psi
- 2.1 in
- Suggested nominal size
- 1-1/2" or larger
- Velocity guide
- Keep under 20 ft/s in mains
Quick answer
Compressed air lines are sized so total pressure drop stays under about 2 psi from compressor to tool.
drop rises with length and falls with the fifth power of diameter
How to use the Compressed Air Pipe Size Calculator
- 1Enter the flow the line must carry and the operating pressure.
- 2Include the full run length plus equivalent length for fittings.
- 3Increase diameter until pressure drop is under 2 psi.
Worked example
Using the values the calculator loads with:
Inputs
- Flow40 SCFM
- Line pressure100 psi
- Pipe length100 ft
- Pipe inside diameter0.75 in
Results
- Pressure drop346.47 psi
- VerdictToo much — increase pipe size
- Minimum diameter for 2 psi2.1 in
- Suggested nominal size1-1/2" or larger
- Velocity guideKeep under 20 ft/s in mains
Frequently asked questions
Does 1 psi matter?
Every 2 psi of drop costs about 1% in compressor energy, and tools lose torque quickly below rating.
Loop or dead-end?
A ring main halves the effective length and evens out pressure at every drop.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.