How to read a dash number
A dash number is not a diameter. The series it sits in fixes the cross section - the thickness of the cord - and the position within the series sets the inside diameter. So every 2xx size shares one cross section and differs only in bore, which is why a seal that leaks is so often the right inside diameter in the wrong series. The fractional names are nicknames rather than dimensions: the 1xx cord is called 3/32 and measures 0.103 inches.
Outside diameter is a sum, not a published figure
Outside diameter is not a published AS568 dimension. The standard fixes the inside diameter and the cross section, and the outside diameter follows from them: OD = ID + 2 x CS. Every outside diameter on this site is that sum, not a figure read from a table, and it inherits both tolerances rather than carrying one of its own.
What is here, and what is not
This chart carries the five cross-section series - 0xx, 1xx, 2xx, 3xx and 4xx. It does NOT carry the 900 series, the 20 straight-thread boss gaskets AS568 also lists: those are boss seals rather than O-rings in the usual sense and are sized to the fitting, so they are left out rather than mixed in. Dash numbers -400 to -424 are carried and flagged: two of the four catalogues list them under AS568, and the AS568B list of 369 standard sizes does not.
Of the 374 dash numbers listed, 349 are AS568B standard sizes and 25 are the catalogued -400 to -424 block, marked as such on every page they appear. Every dimension was read from at least two independent published tables before it was printed.