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Workshop Dust Collection Sizer
The airflow rating on a dust collector's box is measured with no ductwork attached. Size it against what your tool actually needs after duct losses.
Why duct losses matter
Every dust collector's rated airflow (m³/h) is measured straight off the impeller with no ductwork attached. Once you run flexible or rigid pipe from the collector to the tool, friction against the duct walls creates static pressure loss, and the airflow that actually reaches the tool drops — sometimes dramatically over a long, narrow run.
Sizing the collector, not just the duct
This tool starts from the airflow your tool actually needs for effective chip and dust capture, then works backwards through an estimated percentage loss per metre of duct (higher for narrow ducting, lower for wider) to show the collector rating you'd need to still deliver that airflow at the tool end of the run.
Frequently asked questions
Why does duct length reduce the airflow at the tool?
Air moving through ductwork loses energy to friction against the pipe walls and turbulence, which shows up as static pressure loss. The longer and narrower the run, the more of the dust collector's rated airflow is lost before it ever reaches the tool.
Why does duct diameter matter so much?
Smaller diameter ducting moves air faster for the same airflow volume, and friction losses increase sharply with air velocity. Stepping up from a narrow flex hose to a larger rigid pipe can dramatically cut static pressure loss over the same distance.
Does this account for fittings, bends and blast gates?
No — this is a simplified straight-run estimate based on duct length and diameter alone. Elbows, Y-fittings, flexible hose and partially open blast gates all add extra resistance, so treat the result as a minimum and lean toward a collector rated somewhat higher.
What happens if my dust collector is undersized?
Chips and fine dust won't be captured effectively at the tool, which means more mess in the shop, faster clogging of filters, and more airborne fine dust — the kind most worth capturing for health reasons.