— We present an easy-to-use calibration method for MEMS inertial sensor units based on the Factorization method which was originally invented for shape-and-motion recovery in computer vision. Our method requires no explicit knowledge of individual motions applied during calibration procedure. Instead a set of motion constraints in the form of an innerproduct is used to factorize sensor measurements into a calibration matrix (that represents intrinsic sensor parameters) and a motion matrix (that represents acceleration or angular velocity). These motion constraints can be collected quickly from a lowcost calibration apparatus. Our method is not limited to just triad configurations but also applicable to any coordination of more than three sensor elements. A redundant configuration has the benefit that all the calibration parameters including biases are estimated at once. Simulation and experiments are provided to verify the proposed method.