The optimization of integrated spiral inductors has great practical importance. Previous optimization methods used in this field are either too slow or depend on very simplified assumptions in the device modeling which result in the algorithm only applicable to low-frequency cases. In this paper, we propose using the sequential quadratic programming (SQP) approach to optimize the on-chip spiral inductors. A physical model based on first principles is used in the back-end device-parameter extraction engine which makes the algorithm suitable to the optimization at any frequency range. In addition, compared with enumeration, which is used in many inductance optimization packages, our experiments show that the SQP algorithm can achieve at least an order of magnitude speedup while maintaining the same quality of the optimized design.