Metal foil eddy currents induced with flat (stacked spiral) induction coils are calculated numerically using an almost exact approach. Edge bake phenomena of metal foils are investigated to develop a new all-over heat adhesion method. As our aim, this approach is constructed with basic formulas for theoretically analyzing the induction heating phenomena. Fundamental equations in electromagnetic theory are used and a calculation method of self-inductance is developed using the Neumann's formula. These results can be applied to certification of various computer simulations by software on the market concerned with the eddy current.