To choose the most suitable RF coil available for an MRI study, we propose a procedure which uses a calibrated phantom, a 3D gradient-echo sequence, and an automatic post-processing tool available on the web. This tool generates a report which contains the measurement of a SNR with uniform volumes located in the depth. The post-processing could be done on MR images acquired on most main MRI vendors (Siemens, GE, Philips and Bruker) with prior verification of applied scaling or filtering. RF coil characterization results performed on at 4.7T and 7T were compared. The tool can be used for quality control.