Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Nominal impedance (Ω)

Required number input.

Tolerance (%)

Required number input.

Calculate the lower and upper impedance bounds from a nominal controlled-impedance value and a symmetric percentage tolerance. It does not calculate trace geometry or account for asymmetric fabrication variation. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Minimum ohm

The resulting minimum ohm returned as a number.

Maximum ohm

The resulting maximum ohm returned as a number.

• PCB trace calculations depend on finished copper thickness, geometry, dielectric stack-up, temperature rise criterion, ambient, neighboring conductors, return path, frequency, surface finish, and fabrication tolerance. IPC equations are approximations, not a substitute for the board fabricator's stack-up or field solving.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

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