We present one upper bound on the size of non-linear codes and its restriction to systematic codes and linear codes. This bound is independent of other known theoretical bounds, e.g. the Griesmer bound, the Johnson bound or the Plotkin bound, and it is an improvement of a bound by Litsyn and Laihonen. Our experiments show that in some cases (the majority of cases for some q) our bounds provide the best value, compared to all other theoretical bounds.