We combine constraints from analyticity with experimental electron-proton scattering data to determine the proton magnetic radius without model-dependent assumptions on the shape of the form factor. We also study the impact of including electron-neutron scattering data, and ππ → NN data. Using representative datasets we find for a cut of Q 2 ≤ 0.5 GeV 2 , r p M = 0.91 +0.03 −0.06 ± 0.02 fm using just proton scattering data; r p M = 0.87 +0.04 −0.05 ± 0.01 fm adding neutron data; and r p M = 0.87 +0.02 −0.02 fm adding ππ data. We also extract the neutron magnetic radius from these data sets obtaining r n M = 0.89 +0.03 −0.03 fm from the combined proton, neutron, and ππ data.