The ordered breakup pattern of a thin layer of ferrofluid drop subjected to a uniform perpendicular field is experimentally investigated. The results confirm a universal pattern formation containing numerous breaking droplets of a uniform size, which is independent of the initial area of ferrofluid drop and the propagating directions of the formation waves. Two quantitative observations regarding the size and number of breaking droplets are concluded. Both the experiments and theoretical analysis show the correlation between the diameter of breaking droplets (d) and magnetization strength (M) can be characterized as d∝1/M2. The uniform size of breaking droplets under a constant field strength results in a linear proportionality between the number of breaking droplets (N) and the initial area of ferrofluid drop (A) as N∝A, which is verified by the experiments.