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Woodworking Math

Dust collection calculator

List the machines you will connect and which of them run at the same time. You get the airflow each one needs at its dust port, from the machine makers' own manuals, the duct size for each branch and for the main that keeps chips moving, and the airflow your collector has to deliver.

Median of 3 sources

Only two sources publish this: Grizzly Industrial and SawStop

Collector must deliver

500 CFM

850 m³/h, at your system's resistance

Main duct: 4 in (102 mm) at 5,730 FPM

  • Machine 1 branch: 4 in (102 mm) at 5,730 FPM

Static pressure (the resistance of the ducts, fittings and filter) is not estimated here: the only published loss table we found is Grizzly’s, printed in many of its manuals, and one table is not enough to give you a number. Read your collector’s fan curve at your system’s resistance, not its maximum airflow.

Why: 500 CFM through a 4 in main at 5,730 FPM: size the collector to deliver 500 CFM at your system’s resistance.

Why these numbers?

  1. The situation

    The machines that run at once need 500 CFM together (or the largest one alone, if none run together).

    From your input: your machines and which run together

  2. What that means

    Chips stay airborne only above a minimum air speed: Grizzly asks for at least 4,000 FPM in branches; SawStop gives 20 m/s (3,937 FPM). This layout uses 4,000 FPM.

    Two sources: Grizzly Industrial and SawStop , sources [1, 2]

  3. So

    Airflow = speed × duct area, so the largest duct that keeps 4,000 FPM is 24 √(500 ÷ (π × 4,000)) = 4.79 in; the standard size at or under it is 4 in.

    Arithmetic: exact by definition

  4. The number

    Static pressure (the resistance of the ducts, fittings and filter) is not estimated here: the only published loss table we found is Grizzly’s, printed in many of its manuals, and one table is not enough to give you a number. Read your collector’s fan curve at your system’s resistance, not its maximum airflow.

    One source: Grizzly Industrial, the only maker we found that publishes a duct loss table , sources [1]

Sources

  1. Grizzly Industrial, G0442/G0601 cyclone dust collector manual: designing the system (pp. 36–38: CFM by port size, main and branch velocity, branch sizing, duct resistance), read 2026-11-07
  2. SawStop, Professional Cabinet Saw owner’s manual (EU, Nov 2025), p. 37: minimum dust collector 850 m³/h, 4" inlet, conveying velocity 20 m/s, read 2026-11-07
  3. Grizzly Industrial, G0690 10" cabinet table saw manual: recommended CFM at dust port, 400 CFM, read 2026-11-07
  4. Laguna Tools, Fusion 2 table saw manual, specifications: dust outlet 4", minimum 500 CFM, read 2026-11-07
  5. Grizzly Industrial, G0555LX 14" bandsaw manual: minimum CFM at dust port, 400 CFM, read 2026-11-07
  6. JET (JPW Industries), JWBS-14SFX 14" bandsaw manual: 4" port, minimum extraction 400 CFM, read 2026-11-07
  7. Laguna Tools, 14|BX bandsaw manual: two 4" dust ports, collector of at least 1,000 CFM, read 2026-11-07
  8. Grizzly Industrial, G0815 13" planer manual: minimum CFM at dust port, 400 CFM, read 2026-11-07
  9. JET (JPW Industries), JWP-13BT 13" planer manual: dust collector capacity of 550 CFM, read 2026-11-07
  10. Grizzly Industrial, G0656X 8" jointer manual: recommended CFM at dust port, 400 CFM, read 2026-11-07

How we source these numbers

How many CFM each machine needs

Machine makers print the airflow their dust port needs in the manual. Where three makers give a figure the calculator starts from the median, where two do it names both, and where only one does it asks for your manual's figure instead.

Airflow each machine class needs at its dust port, by maker
MachineMakers' figures (CFM)Used
Table saw, 10 in cabinet or hybridGrizzly Industrial 400; Laguna Tools 500; SawStop 500500 CFM
Bandsaw, 14 inGrizzly Industrial 400; JET 400; Laguna Tools 1,000400 CFM
Planer, 13 inGrizzly Industrial 400; JET 550475 CFM
Jointer, 6–8 inGrizzly Industrial 400your manual

Several makers state what their machine needs from the collector rather than at the port (JET's planer, Laguna's two-port bandsaw); those are counted as printed. SawStop states 850 m³/h, which is 500 CFM.

Duct size by air speed

Grizzly asks for at least 4,000 FPM in branch ducts and 3,500 FPM in the main; SawStop gives 20 m/s (3,937 FPM) for the duct to its saw. The calculator sizes every duct at the velocity you set, 4,000 FPM to start.

Airflow is air speed times the duct's area, so for a round duct the largest diameter that keeps the speed up is 24 × √(CFM ÷ (π × FPM)) inches, and the calculator takes the standard size at or under it. At 4,000 FPM that gives a 4 inch branch for 400 to 500 CFM, 5 inch for 600 to 700 and 6 inch for 800 to 1,000, the same as Grizzly's own branch table.

Only two sources publish this: Grizzly Industrial and SawStop

Sizing the collector

  • A machine’s CFM figure is what its port needs, not the rating of the collector: the airflow that arrives depends on the collector, the length and kind of duct, the fittings and how many blast gates are open.

    Two sources: Grizzly Industrial and Laguna Tools , sources [1, 2]

  • Use rigid smooth duct and gradual bends where you can: flexible hose and sharp 90° elbows add the most resistance.

    One source: Grizzly Industrial, a dust collector maker, in its system-design manual , sources [3]

Sources

  1. Grizzly Industrial, G0690 10" cabinet table saw manual: recommended CFM at dust port, 400 CFM, read 2026-11-07
  2. Laguna Tools, 14|BX bandsaw manual: two 4" dust ports, collector of at least 1,000 CFM, read 2026-11-07
  3. Grizzly Industrial, G0442/G0601 cyclone dust collector manual: designing the system (pp. 36–38: CFM by port size, main and branch velocity, branch sizing, duct resistance), read 2026-11-07

Dust and your health

  • Wood dust is a known human carcinogen: the National Toxicology Program lists it as known to be a human carcinogen and IARC places it in Group 1.

    One source: OSHA, the US workplace safety regulator , sources [1]

  • Wood dust impairs lung function, and western red cedar dust has been shown to cause asthma.

    One source: OSHA, the US workplace safety regulator , sources [1]

  • Significant accumulations of fine wood dust are a fire and explosion hazard, and airborne dust can create the potential for a dust explosion.

    One source: OSHA, the US workplace safety regulator , sources [1]

Sources

  1. OSHA, Wood Dust: Hazard Recognition, read 2026-11-07

For the guards and rules on the machines themselves, see woodworking machine safety.