We introduce the notion of bi-Lipschitz equivalence of ideals and derive numerical invariants for such equivalence. In particular, we show that the log canonical threshold of ideals is a bi-Lipschitz invariant. We apply our method to several deformations f t : (C n , 0) → (C, 0) and show that they are not bi-Lipschitz trivial, specially focusing on several known examples of non µ *-constant deformations.