Designing LED PCBs demands far more than applying standard PCB design rules. While conventional circuit boards prioritize electrical performance and signal integrity, LED PCBs must engineer thermal pathways as meticulously as electrical circuits—because heat, not electrons, determines whether your LED product succeeds or fails. A single design oversight—insufficient copper pour, poorly placed thermal vias, or inadequate LED spacing—can transform a promising LED design into a field failure nightmare. This comprehensive 2026 guide walks you through every critical aspect of LED PCB design, from substrate selection and power calculations through advanced thermal simulation and design for manufacturing. Whether you’re designing your first LED circuit or optimizing an existing product, you’ll discover proven techniques for maximizing LED lifespan, ensuring uniform light output, and avoiding the costly mistakes that plague poorly designed LED PCBs. Learn how proper thermal via placement can reduce junction temperatures by 20-30°C, why 2oz copper outperforms 1oz despite minimal cost increase, and when thermal simulation transitions from optional to mandatory.