This result states minimal surface equation for graphs: given U R m be open and let u: U R be a function with u C 2(U;R). The graph of u in R m+1 is minimal if and only if div ( u 1+| u| 2 )=0 in U.. It is useful in the structure and regularity of minimal surfaces, where variational identities, curvature estimates, and compactness arguments control geometric objects.