CNC Dust Collection CFM Calculator
Dust collection airflow for a CNC router or mill.
Enter your values
Enter the dust port diameter in in.
Enter the active ports you are working with.
Enter the transport velocity in FPM.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Required airflow
- 349 CFM
- Per port
- 349 CFM
- Transport velocity used
- 4,000 FPM
- Collector filter area
- 43.6 sq ft (at 8:1 air-to-cloth)
Quick answer
A CNC router typically needs 350-800 CFM at the hood depending on spindle size and enclosure, delivered at 3500-4500 FPM in the hose for chip transport.
CFM = port area x transport velocity
At a glance
| What it does | Dust collection airflow for a CNC router or mill. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Dust port diameter, Active ports, Transport velocity |
| Main output | Required airflow |
| Formula | CFM = port area x transport velocity |
| Cost | Free — no sign-up, no download |
How to use the CNC Dust Collection CFM Calculator
- 1Measure the dust port diameter(s) at the CNC hood.
- 2Enter the number of ports open simultaneously.
- 3Keep hose velocity at 3500-4500 FPM to keep chips moving without settling.
Inputs explained
- Dust port diameter(in)
- Enter the dust port diameter in in.
- Active ports
- Enter the active ports you are working with.
- Transport velocity(FPM)
- Enter the transport velocity in FPM.
Worked example
Using the values the calculator loads with:
Inputs
- Dust port diameter4 in
- Active ports1
- Transport velocity4000 FPM
Results
- Required airflow349 CFM
- Per port349 CFM
- Transport velocity used4,000 FPM
- Collector filter area43.6 sq ft (at 8:1 air-to-cloth)
Frequently asked questions
Can a shop vac handle a CNC router?
Small routers with a single 2.5 in port can work with a strong shop vac, but larger routers need a real dust collector.
Why does velocity matter so much?
Below about 3500 FPM, heavier chips and dust settle in horizontal runs and eventually clog the line.
What do I need to enter into the CNC Dust Collection CFM Calculator?
Just 3 values: dust port diameter, active ports, transport velocity. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the CNC Dust Collection CFM Calculator work out the answer?
A CNC router typically needs 350-800 CFM at the hood depending on spindle size and enclosure, delivered at 3500-4500 FPM in the hose for chip transport. It applies the formula CFM = port area x transport velocity and shows the working so you can check each step by hand.
Is the CNC Dust Collection CFM Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.