An alternative estimation of the dissipated power allocation in OLED based on the analysis of the transverse propagating electromagnetic (EM) waves along the layers of the OLED is proposed. The dissipated power mode fraction has been conventionally defined by dividing the normalized in-plane wavevector with the cut-off of the transvers propagation, which is equal to the refractive index of the each layer, according to the ray-optical sense. Instead, we adopt the propagating EM eigenmode in OLED, physically confining a piece of the power in the thin film layers. The spectral integral is described as the extension of Cauchy’s principal value integral at the eigenvalue of the in-plane wavevector of the EM propagating mode along the layers; and is derived to the product of the peak value of the spectral distribution and the imaginary part of the eigenvalue of the in-plane wavevector multiplied by π, with the aid of the self-consistent scheme. For the simple model of two layers between semi-infinite substrate and metal, the present estimation is closer than the conventional one to the quantitative grasping the dipole radiation’s allocation into the extraction and the confinement.