8 x 11 is not a standard size of graph paper. Graph paper standards are measured by the dimensions of the grid boxes, not by the overall size of the paper they are printed on and the boxes are always identical in length and width.
There are no countries that use paper with dimensions of 8 by 11 as their standard-sized sheet. In the United States, letter-size dimensions, i.e. 8.5 by 11 inches, are the most common for single sheets of paper, but most other countries use A4-sized sheets that are slightly narrower and longer. Furthermore, since the standards for graph paper refer to the grid, not the paper size, graph paper may be printed on sheets with arbitrary dimensions.
There are several standard sizes for graph paper, ranging from 1/10 of an inch to 1/2 inch. The most common standard size of graph paper features a grid made up of boxes that are 1/4 inch long and wide.