PCB Trace Width and Clearance: How to Choose

Trace width and clearance affect whether a board works safely and can be manufactured.

Trace width

The width depends on the current the trace carries, the copper thickness and how much temperature rise you accept. Use a calculator based on the IPC-2221 standard, and make power traces wider than signal traces. Signal traces are often a fraction of a millimetre wide.

Clearance

Clearance is the gap between copper features. Higher voltages need larger gaps for safety. Follow the standard that applies to your product.

Manufacturing limits

Never go below the manufacturer's minimum width and spacing. Staying above the minimum usually improves reliability and yield.

Good habits

• Use wider traces or copper planes for power.
• Keep sensitive traces short.
• Keep widths consistent unless there is a reason to change them.

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