Required CFM
400
Main Duct
5"
Static
1.8" wg
Sizing: 1 machine(s) running at once
Calculated duct: 4.3" (rounded up to 5")
Target velocity: 4000 FPM
Inputs
Result
Largest single tool determines minimum CFM
Inputs
Result
Both tools running at once
Most single-tool setups need 400-800 CFM. A table saw requires 400 CFM, a planer 400 CFM, and a small sander 50 CFM. Size your collector for the highest-demand tool running at once plus 25% buffer.
| Machine | CFM Needed | Port Size | Priority |
|---|---|---|---|
| Table Saw | 400 | 4" | High |
| Planer | 400 | 4" | High |
| Jointer | 350 | 4" | High |
| Bandsaw | 350 | 4" | Medium |
Main trunk lines should be 6" for most small shops. Branch lines are typically 4" for large tools and 2.5" for small tools. The duct must maintain 4,000 FPM air velocity to keep dust suspended.
Static pressure is the resistance your duct system creates. Estimate about 0.05 inches water gauge per foot of duct, plus add 5 equivalent feet for each 90-degree elbow. Your collector must overcome total static pressure.
For a one-tool-at-a-time small shop, a 1HP collector (650 CFM) handles most tools. If you run multiple tools or have long duct runs (20+ feet), upgrade to 2HP (1,200 CFM). Always check static pressure capacity.
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Last Updated: Mar 20, 2026
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