Tubing and fitting dimensions may not be specified like you would think. Tubing outside diameters are typically larger than the order size. To compensate for this, the openings of the fittings are sized to be slightly larger than the actual tubing size they are specified for. For example a 3/4" fitting actually has a 1" inside diameter. This is sized so that 3/4" EMT which has an actual outside diameter of 15/16" will fit inside the fitting. For more information see the table below.

Fittings ID is the Inside Diameter of the fitting.

Tubing OD is the Outside Diameter of the tubing that is used for this fitting size.
Order SizeActual Fitting ID*Actual Tubing OD*Type Tubing
3/4"1"15/16"Electrical Metal Conduit (EMT)
1"1 3/16"1 1/8"Electrical Metal Conduit (EMT)
1 3/8"1 3/8"1 5/16"Chain link Fence Tubing
1 5/8"1 3/4"1 11/16"Chain link Fence Tubing
1 7/8"1 15/16"1 7/8"Chain link Fence Tubing
*All sizes are rounded to the nearest 1/16" of an inch.