Designing a power converter requires a good prediction of electrical quantities. Steady-state waveforms are needed but using a time-domain simulator to determine accurately these steady-state waveforms is generally too slow, so the designer usually uses a simplified analytical formulation to estimate these electrical quantities. This is not always accurate, must be repeated for each new circuit, and can be tedious for complex topologies. In this paper we show that a frequency-domain solver based on a Modified Nodal Analysis of the circuit can be used to obtain accurate results in little time even for a complex circuit, which makes it an efficient building block for a design tool. Accuracy and speed is demonstrated using comparisons with the steady-state analysis of Plecs ®-which relies on a time-domain solver.