What volume will various sized gelatin capsules hold

I use size ‘O’ gelatin capsules and I have measured that they hold about 1/8th tsp. each. How much volume can OOO, OO and 1 size gelcaps hold. Do they have anything bigger than OOO or smaller than 1?

The Google search that worked was: gelatin capsules specifications.

The most helpful site I found was Torpac, which gives sizes in ounces or millilitres for 15 different sizes of capsules. They range from the very very tiny size 5 (0.13 ml) to the unsettlingly large Su07 (28 ml). All the ones bigger than OOO (1.37 ml) have “veterinary names”.

The other common sizes are OO (0.95 ml), O (0.68 ml), and 1 (0.5 ml).

there are 5ml in 1 teaspoon, so 5/.68 is 7.35, which is close to the 1/8th that I came up with.