calc.engineer / PCB & Electronics / Trace Width

Trace Width v1.0.0

Calculates the minimum PCB trace width for a given current using the IPC-2221 standard formula. The IPC-2221 empirical equation relates current capacity to cross-sectional area and temperature rise: I = k * dT^0.44 * A^0.725, where k=0.048 for external layers and k=0.024 for internal layers. Supports configurable copper weight (oz/ft^2) and temperature rise. Also computes approximate DC resistance per centimeter. Essential for power delivery, high-current motor drivers, and ensuring PCB reliability. Chain from voltage_divider or impedance_match to verify trace sizing for computed currents.

← from voltage_divider← from impedance_match
Required current capacity in amperes (A).
Copper weight in ounces per square foot. 1 oz/ft^2 = 1.37 mil (34.8 um) thickness. Common values: 0.5, 1, 2.
Allowable temperature rise above ambient in degrees Celsius. IPC-2221 standard uses 10, 20, or 30 C.
PCB layer type. External layers dissipate heat better (k=0.048); internal layers use k=0.024.
Fill in the inputs and Compute to see the structured result.

From an agent (MCP) or the API

curl -X POST https://calc.engineer/api/trace_width \
  -H "Content-Type: application/json" \
  -d '{"current_amps": …, "copper_oz": …, "temp_rise_c": …}'

MCP: connect to https://calc.engineer/mcp and call trace_width.

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