The eddy-current model is an approximation of the full Maxwell equations. We will give estimates for the modeling error and show how the constants in the estimates are influenced by the geometry of the problem. Additionally, we analyze the asymptotic behavior of the modeling error when the angular frequency tends to zero. The theoretical results are complemented by numerical examples using high order finite elements. These demonstrate that the estimates are sharp. Hence, this work delivers a mathematical basis for assessing the scope of the eddy-current model.