There are about 294 2x4s in a bundle. This is based on a bundle size of 1,568 foot board measures. One 2x4x8 is equal to 5.33 foot board measures.
Foot board measure is calculated by multiplying the thickness, width and length of a board and then dividing it by 12. Bundle size is adjusted for the length of the board, so there are the same amount of 2x4s in a 2x4x8 bundle as there are in a 2x4x9 bundle. Foot board measure is basically a calculation of how many boards of a particular size that it takes to build a 12-by-12-inch square block, which means that length takes on a more significant role in the calculation of bundle than width and thickness.