A covering array CA(N ; t, k, v) is an N × k array A whose each cell takes a value for a v-set V called an alphabet. Moreover, the set V t is contained in the set of rows of every N × t subarray of A. The parameter N is called the size of an array and CAN (t, k, v) denotes the smallest N for which a CA(N ; t, k, v) exists. It is well known that CAN (t, k, v) = Θ(log 2 k) [8]. In this paper we derive two upper bounds on d(t, v) = lim sup k→∞ CAN (t,k,v) log 2 k using the algorithmic approach to the Lovász local lemma also known as entropy compression.