An A4 size paper bundle typically refers to a package of A4 sheets, often used for printing, copying, or writing. A4 is a standard paper size of 210 x 297 millimeters (8.27 x 11.69 inches). The number of sheets in a bundle can vary, but common quantities include: 500 sheets: Standard ream of paper, usually sold as a single package. 1000 or more sheets: Often referred to as a bundle or box, typically containing multiple reams.