The material and grade of a magnet refer to a set of properties which ultimately yield the magnet's performance.
The strength of a magnet can be found in the magnet specification known as BHmax, which is the maximum energy density of a magnet. This is defined in Mega Gauss Oersteds, or MGOe. For Neodymium (NdFeB) Magnets the BHmax will range, in general, from 30 MGOe to 55 MGOe.
The exact magnetic strength will be determined by its grade mostly, for example, regarding the same dimension magnet Dia10*5MM, the higher the grade is, the stronger the strength will be.
Neodymium magnets produce the highest MGOe of any permanent magnet material. The most common grades of Neodymium magnets are N33, N35, N38, N40, N42, N45, N48, N50, N52, and N55.