PCB Trace Current Calculator

External traces are on the outer layers of the PCB and have better heat dissipation due to air exposure. Internal traces are buried within the PCB layers and have reduced current capacity because heat dissipation is limited by the surrounding dielectric material.

Thicker copper layers can carry more current because they have a larger cross-sectional area. Standard thicknesses are 0.5, 1, 2, and 3 oz/ft², with 1 oz/ft² being the most common. Each doubling of thickness roughly doubles the current capacity.

A common design rule is to limit temperature rise to 10°C above ambient for reliable operation. Higher temperature rises (up to 40°C) may be acceptable for non-critical applications, but this reduces component lifespan and reliability.

Yes, this calculator uses the IPC-2221 standard formulas for PCB trace current capacity. IPC-2221 is the widely accepted industry standard for printed circuit board design guidelines and current carrying calculations.

Trace length affects resistance, voltage drop, and power dissipation but not the maximum current capacity itself. Longer traces have higher resistance, leading to greater voltage drops and power losses at the same current level.

The IPC-2221 formulas provide good estimates for most applications, typically within 10-20% of actual values. Real-world factors like PCB stackup, via thermal effects, and component heat generation can affect actual current capacity.

Exceeding the current limit will cause the trace temperature to rise beyond the specified limit, potentially leading to PCB delamination, component damage, solder joint failure, or even trace burnout in extreme cases.

Yes, voltage drop becomes important for power delivery traces, especially in low-voltage high-current applications. Even if current capacity is adequate, excessive voltage drop can cause circuit malfunction or reduced performance.