In this paper we present a least-squares minimization approach to depth determination from an electromagnetic anomaly profile. In EMI method a transmitter coil radiates an electromagnetic field and the anomalous signal from the ground is detected by a receiver coil. When a conductor is present, its response can be separated in two modes. Eddy-current mode is circulating inside the conductor and current-channeling is crossing the boundary between the conductor and the background medium. The responses differ depending on the geometry of transmitter, receiver, and conductivities. We consider a situation that only the eddy current response is measured in the receiver coil. We apply the Krawczyk method, which is an interval computation technique, to solve this nonlinear equation. We apply this method to synthetic data with and without random error. In all cases, the depth solution obtained provides reasonable results.