Winding and core geometries are described for a matrix transformer constructed from integrated core and z-folded flex circuits. The magnetizing inductance is derived using the reluctance method and exploiting structural periodicity and symmetry. The internal leakage inductance is computed from the magnetic field distribution, and the interconnect leakage inductance from inductance formulas and current distribution. The results show that the interconnects are responsible for most of the leakage inductance. The modeling predicts inductance values that agree well with experimental measurements. >