Development of an approach extracting quantitative information regarding the energetic behavior of core electrons from photoelectron measurements of the surface and size dependence of core level variation has long been a challenge though the surface- and size-induced core level shifts of materials have been intensively investigated. Here we show that a combination of the tight binding theory, the bond order-length-strength (BOLS) correlation, and the measured data from Pt(111) surface and Pt nanocrystals has led to an approach for this purpose. With the developed method, we have analyzed the 4f7/2 core-level shift of four sets of data gained from the Pt(111) surface and four sets of data from Pt nanoclusters deposited on graphite and carbon nanotubes. Reconciliation of the measurements turns out that the Pt 4f7/2 binding energy of an isolated Pt atom and its bulk shift to be 67.67 and 2.99 eV, respectively. Consistency between the BOLS calculations and photoelectron measurements clarifies that the size- and surface-induced positive energy shifts originate from the broken-bond-induced local strain and the associated quantum trapping in surface of skin-depth while the bond length and binding energy in the core interior remain their bulk values. Reconciliation of the photoelectron measurements of both Pt(111) surfaces and Pt nanostructures evidence the reliability of the developed approach.