Reported energy conversion efficiencies in biological, electro-mechanical, photovoltaic, and computational systems routinely overpredict usable energy delivered under real operating conditions. Field-scale performance of photosynthetic organisms, solar power plants, electric drivetrains, and information-processing hardware is consistently limited to a small fraction of laboratory or nameplate efficiencies, despite decades of optimization. This discrepancy arises because conventional efficiency metrics implicitly assume single-stage conversion, neglecting the sequential processes of energy absorption, transport, regulation, and transformation, each governed by irreversible thermodynamic constraints. Here we introduce a Unified Energy Survival–Absorption–Conversion Law that replaces scalar efficiency with a physically grounded survival formulation capturing multi-stage energy degradation. We define an energy survival factor, Ψ=AE/TE+ε, where AE represents absorbed energy successfully retained within the system boundary, TE denotes transport and environmental dissipation losses, and ε captures irreducible entropy-generating losses mandated by the second law of thermodynamics. Unlike traditional efficiency ratios, Ψ explicitly accounts for spatial, temporal, and regulatory energy attrition and remains invariant across biological and engineered domains. By coupling ΨΨ with an internal conversion competency term Cint, derived from the Life-CAES reaction–transport framework, we obtain a universal performance law: Euseful=Ein⋅Ψ⋅Cint. This formulation decomposes usable energy yield into independently measurable survival and conversion components, enabling direct identification of dominant loss pathways. Application across representative systems—plant bioenergetics, photovoltaic installations, electric propulsion, and data-center computing—demonstrates that observed field-scale outputs (typically 0.1–5% of incident energy in biological systems, 10–25% in photovoltaics, 60–90% in electric drives, and <1% in large-scale computing) emerge naturally from survival-limited rather than conversion-limited dynamics. The unified law resolves long-standing inconsistencies between laboratory efficiency and real-world performance, provides a common analytical language across living and engineered systems, and establishes fundamental survival constraints on energy utilization. This framework enables more accurate performance prediction, system-level optimization, and realistic upper bounds for future energy technologies. Please check the attachment for details