Stop guessing at the hardware aisle
Measure the port. Measure the hose.
Get the adapter guidance you need.
Enter two measurements. The calculator determines which end must insert, which end must fit over, and whether you should search for a straight coupler, reducer, expander, or a stepped, universal, flexible, or custom solution.
No model-number guessing
No account required
No measurements stored
Free calculator
Find your connection
Your result
Connection guidance
HOSE SIDE
TOOL SIDE
Airflow check
Shop the result
These buttons open retailer searches using the exact measured dimensions, nearest nominal labels when applicable, and required end direction. The wording is guidance, not a verified product match. Confirm the listing’s exact ID/OD dimensions before ordering.
Before you buy
Thirty-second measuring guide
Inside diameter and outside diameter are not interchangeable.
Remove existing adapters
Measure the actual hose cuff or tool port—not a loose accessory sitting on it.
Measure straight across
Use callipers when possible. Measure the widest inside opening for ID or the widest outside edge for OD.
Check the shape
Tapers, locking tabs, oval ports, and proprietary clips can defeat an otherwise correct diameter match.
Common questions
What the calculator can—and cannot—tell you
Why does a “2½-inch” hose sometimes not measure exactly 2½ inches?
Dust-collection sizes are often nominal. Some brands describe the hose opening, some the cuff, and others the port family. This tool shows your exact measured millimetre value first and adds the nearest common nominal size only as a shopping aid.
Does this guarantee a perfect fit?
No. It determines the required diameter and connection direction. You still need to verify taper, wall thickness, locking tabs, thread, and material flexibility on the product listing.
Why can the result say “no verified standard one-piece match”?
The calculator does not use a manufacturer product database. When a measurement is non-standard or the size gap is large, it reports the gap and recommends broader stepped, universal, flexible, trim-to-fit, or custom searches instead of inventing a specific adapter chain.
Why does it warn about airflow?
A sharp reduction in cross-sectional area can restrict airflow and increase clogging. The calculator flags large changes but does not replace your tool or dust collector manufacturer’s operating guidance.
Are the store buttons affiliate links?
Retail links are currently standard search links unless explicitly marked. When affiliate links are enabled, we may earn a commission at no extra cost to you.