PCB Trace Width Calculator
IPC-2221 Standard ā Internal & External Layers
The most accurate free PCB trace width calculator online. Based on the IPC-2221 standard, calculate the minimum copper trace width needed to safely carry your target current ā for both external and internal PCB layers ā including trace resistance, voltage drop, and power loss.
What is PCB Trace Width?
The Critical Dimension in Every PCB Layout
PCB trace width is the physical width of a copper conductor routed on a printed circuit board. It is one of the most critical parameters in PCB layout design ā directly determining how much current a trace can safely carry without overheating. An undersized trace causes resistive heating, voltage drop, and eventual board failure. An oversized trace wastes board space and increases manufacturing cost. The PCB trace width calculator below computes the exact minimum width needed for your current, copper thickness, and permissible temperature rise ā following the industry-standard IPC-2221 guidelines.
ā” Current Carrying Capacity
Every PCB trace has a maximum current it can safely conduct. Exceeding the PCB trace current carrying capacity causes resistive heating proportional to IĀ²R ā which can melt solder, delaminate the board, or cause open-circuit failure.
š” Temperature Rise
The PCB trace temperature rise above ambient is directly controlled by trace width and copper thickness. IPC-2221 recommends a maximum ĪT of 10Ā°C for signal traces and up to 20ā30Ā°C for power traces in most applications.
š IPC-2221 Standard
The IPC-2221 standard defines empirical formulas for minimum trace width based on cross-sectional area, using different k-factors for external (0.048) and internal (0.024) copper layers to account for heat dissipation differences.
