Woodshop Branch Duct CFM Calculator
Branch duct sizing for one woodshop dust collection machine.
Enter your values
Choose one of: Table saw (350 CFM), Jointer (400 CFM), Planer (600 CFM), Wide belt sander (800 CFM).
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 branch CFM
- 350 CFM
- Branch duct diameter
- 4 in
- Blast gate
- Open only this branch's gate when running the machine
- Static loss note
- Add 0.02-0.04 in wc per 10 ft of smooth pipe plus fittings
Quick answer
Branch ducts to individual woodworking machines are typically sized for 350-800 CFM at 3500-4000 FPM depending on the tool.
Duct diameter = sqrt(4 x CFM / (pi x velocity)) x 12
At a glance
| What it does | Branch duct sizing for one woodshop dust collection machine. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Machine, Transport velocity |
| Main output | Required branch CFM |
| Formula | Duct diameter = sqrt(4 x CFM / (pi x velocity)) x 12 |
| Cost | Free — no sign-up, no download |
How to use the Woodshop Branch Duct CFM Calculator
- 1Pick the machine being ducted.
- 2Confirm 3500-4500 FPM transport velocity for wood dust.
- 3Size the branch duct diameter from the resulting CFM and velocity.
Inputs explained
- Machine
- Choose one of: Table saw (350 CFM), Jointer (400 CFM), Planer (600 CFM), Wide belt sander (800 CFM).
- Transport velocity(FPM)
- Enter the transport velocity in FPM.
Worked example
Using the values the calculator loads with:
Inputs
- MachineTable saw (350 CFM)
- Transport velocity4000 FPM
Results
- Required branch CFM350 CFM
- Branch duct diameter4 in
- Blast gateOpen only this branch's gate when running the machine
- Static loss noteAdd 0.02-0.04 in wc per 10 ft of smooth pipe plus fittings
Frequently asked questions
Why size branches individually?
Each machine has different chip volume and hood design, so a one-size branch either starves large tools or wastes CFM on small ones.
Can I run two machines at once on one collector?
Only if the collector and main trunk are sized for the combined CFM of every gate open at once.
What do I need to enter into the Woodshop Branch Duct CFM Calculator?
Just 2 values: machine, 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 Woodshop Branch Duct CFM Calculator work out the answer?
Branch ducts to individual woodworking machines are typically sized for 350-800 CFM at 3500-4000 FPM depending on the tool. It applies the formula Duct diameter = sqrt(4 x CFM / (pi x velocity)) x 12 and shows the working so you can check each step by hand.
Is the Woodshop Branch Duct 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.