for computing the charge radius at the physical point from the fit results. The charge radius extrapolated to the physical point, while consistent within the error for the two pion mass values, falls short of the experiment by about 15%. The SU(2) results in Table \[table:PFF\_ChPT\_NLO-f\] are similar. The value for the charge radius predicted at the physical pion mass is about 20% smaller than experiment. We find similar values in the previous studies [@brommel; @ETMC; @JLQCD; @RBC] carried out over a similar range of pion mass.

In Fig. \[fig:R2\_ChPT\_NLO-f\] we plot the fit curves of the pion form factor together with curves from the monopole ansatz for the case of $M_\pi=296$ MeV for (a) SU(2) and (b) SU(3) ChPT to NLO. The pion mass dependence of the squared charge radius $\left< r^2\right> (\rm fm^2)$ which results from the fits are given in the panels (c) and (d) for the SU(2) and SU(3) cases, respectively. Filled circles are the estimates from the monopole ansatz, and the asterisk on the left is the experimental value. As indicated in the panels (c) and (d), the NLO ChPT predictions for $\left< r^2\right>$ at 296 MeV are smaller than that obtained from the monopole 