Woodshop Branch Duct CFM Calculator
Branch duct sizing for one woodshop dust collection machine.
Enter your values
ⓘ Live results
Results
- 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
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.
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.
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.