How many holes are there in a standard ten pin bowling ball?

A bowling ball doesn't have any holes in the manufacturing stage.

The most common number of holes drilled is 3 - 2 fingers and a thumb.

In the early days and sometimes found today, there is only one finger and a thumb.

If there's been some hand injury, sometimes an extra finger hole is drilled.

Sometimes there is a counter balance hole drilled at or near the axis point to allow the dynamics of a bowling ball work better for a bowler.

In tenpin bowling, regardless of the number of holes, you are only allowed a certain weight difference at the grip point, where there is top and bottom weight and left and right side weight.