The following conversion chart provides information to help select the proper size barbed fitting and matching thread for your application.
All nominal barbed fitting designations for this website represent the inner diameter (ID) of the tubing for which the barb is designed to fit, e.g. a 1/4″ barb is designed to fit a 1/4″ ID tube. The actual inch or millimeter dimensions represent the outside diameter (OD) of the barb – slightly larger than the tubing ID to insure a proper seal.
Nominal Inch: Barb size designated to match the ID of beverage tubing.
Actual Barb OD (Inch): The actual outside diameter of the barbed fitting in decimal format in inches.
Actual Barb OD (mm): The actual outside diameter of the barbed fitting in millimeters.
Matching Thread: The unified thread standard that is normally used with a nominal inch fitting, e.g. a 1/4″ nut has a 7/16″ 20 UNF thread count.
Nominal Millimeter: Best practice conversion of inch-based fittings onto metric-based beverage tubing, e.g. 1/2″ barb fittings can be used on 13.5 mm OD beverage tubing.