PCB engineering · Calculation tool

PCB Copper Trace Width & Ampacity Estimator

Estimate copper cross-sectional area and trace width using the IPC-2221A curve-fit for external or internal copper layers and 1 oz or 2 oz copper.

IPC-2221A curve fit: I = k × ΔT^0.44 × A^0.725; A (mil²) = (I ÷ (k × ΔT^0.44))^(1/0.725). Width (mil) = A ÷ copper thickness (mil). k=0.048 external; k=0.024 internal. 1 oz≈1.378 mil; 2 oz≈2.756 mil.

Common symptom presets

Presets are illustrative starting points. Review all values against your actual hardware.

Inputs

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Results are theoretical calculations and do not guarantee compatibility, stability, electrical safety, or manufacturer compliance.

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Reference notes

External copperk=0.048 in IPC-2221A curve fit
Internal copperk=0.024 in IPC-2221A curve fit
ScopeEstimate only; IPC-2152 and board-specific validation may be more appropriate

Technical sources

This page is an educational estimate. Use current manufacturer datasheets and the complete applicable standard for design sign-off.