To use the early measured data of tunnel deformation in but analysis, the relationship between these values find final deformation data were studied. Panet`s exponential and fraction equations successfully approximate the convergence of the hard rock tunnels. Measured deformation data of ID location, $U_{1D}$ show that they can be lilted to linear equations but should not be used to estimate potential deformation before measurement, $C_{0}$. Early measured data $U_{1D}$ $U_{2D}$ , and final deformation $ U_{L}$ showed linear correlations. It proved that estimated data of final deformation from early measured ones can be used as input parameters for back analysis.