AbstractThis paper studies the Hardy-type inequalities on the discrete intervals. Firstly, two variational formulas for the optimal constants are introduced. Based on these formulas, an approximating procedure and the known basic estimates of the optimal constants are deduced. Thirdly, as the main innovation of this paper, an improved factor for the upper estimates is presented, which is smaller than the known one and is the best possible. Finally, some comparison results are included for comparing the optimal constants on different intervals.