One of the most confusing parts of setting up dust collection is the hose sizes. Every manufacturer seems to use a different diameter. Shop vac hoses are not the same as dust extractor hoses. Central dust collection ducts are something else entirely.
This guide covers every common hose diameter and what connects to what.
Shop Vac Hose Sizes
Shop vacs use two standard hose sizes based on the barrel size of the unit:
| Hose Size | ID | Typical Use |
|---|---|---|
| 1-1/4 inch | 32mm | 2.5 to 6 gallon shop vacs |
| 1-7/8 inch | 48mm | 8 to 16 gallon shop vacs |
| 2-1/2 inch | 63mm | Large shop vacs and pro vacuums |
The 1-7/8 inch hose is the most common hose size in North American shops. Many users call it a "standard" shop vac hose. But this varies by brand. Ridgid uses 1-7/8 inch on most models. Shop-Vac (now Craftsman) uses 1-7/8 inch on mid-range units. DeWalt and Milwaukee branded shop vacs use 1-7/8 inch.
Dust Extractor Hose Sizes
European-style dust extractors use metric hose sizes. These do not match US shop vac standards.
| Brand | Hose Diameter | Note |
|---|---|---|
| Festool CT series | 27mm OD hose end | Proprietary clip connection |
| Bosch VAC series | 35mm | Larger models use 50mm |
| Mirka dust extractors | 27mm | Compatible with Festool hoses |
| Makita extractors | 36mm | Matches LXT tool ports |
Central Dust Collection Duct Sizes
Fixed central dust collectors use smooth-walled PVC or metal duct. The standard duct sizes are:
- 4-inch duct: standard for most cabinet saws, jointers, and planers in home shops
- 5-inch duct: used with some larger single-stage collectors
- 6-inch duct: used with cyclone dust collectors and larger two-stage systems
Portable tools connect to a fixed duct system via flexible hose drops. A typical setup: 4-inch main duct with 4-to-2.5-inch reducers at each drop, then a 2.5-inch flexible hose to the tool.
The Confusing Part: Inside vs. Outside Diameter
Hose sizing specs switch between ID (inside diameter) and OD (outside diameter) depending on what is being measured. Tool ports are specified by their ID. Hose fittings are specified by their OD. Adapters bridge the two.
Quick rule: when the adapter goes inside something, match its OD to the ID of that thing. When something goes inside the adapter, match the ID of the adapter to the OD of that thing.
Common Mismatches
These are the four most common connection problems in shop dust collection:
- Shop vac hose to Festool tool port: 32mm or 48mm hose OD does not fit 27mm Festool port ID. Needs adapter.
- Makita tool to standard shop vac: 36mm Makita port ID does not seat the 32mm hose end OD. Needs adapter.
- 4-inch duct to 2.5-inch shop vac hose: needs a 4-to-2.5 reducer fitting.
- DeWalt miter saw port to 1-7/8 inch hose: 38mm saw port ID does not match 48mm hose OD. Needs adapter in both directions.
Finding the Right Adapter
Enter your tool brand and model plus your vacuum type in our configurator. It calculates the exact port sizes on both ends and shows you the adapter that bridges them. Takes less than a minute.