A coil calculating device comprises a base, a feeding device, a selector, a guide groove, and a collecting box at the descending of the selector, wherein the width of the guide groove is some larger than the thickness of the coin, the selector comprises a calculating disc, a blade wheel, and a calculating motor, while the calculating disc is arranged with a plurality of coil outlets which diameters are arranged from small to large along the rotation direction of the blade wheel, the blade wheel is provided with a plurality of blades radial arranged, and the coil is vertically inserted between two nearby blades. The invention can calculate many coins in one time to improve efficiency, with reduced product volume, compact structure, and confirmed accuracy via avoided coil accumulation in the calculating disc.