Technology & Computing
PCB Microstrip Differential Impedance Calculator
Estimate the differential impedance of a microstrip trace pair on a PCB from geometry and dielectric constant.
Your inputs
Change any value to update the result instantly.
Differential impedance
87.1338 Ω
Single-ended impedance (Z0)
49.1573 Ω
Trace width
6 mil
Trace spacing
6 mil
This IPC-2141-style approximation is for quick estimates only — use a field-solver tool to verify controlled-impedance designs before fabrication.
Formula and working
Z0 (single-ended, IPC-2141 approx) = 87/√(εr+1.41) × ln(5.98h/(0.8w+t)); Zdiff ≈ 2×Z0×(1 − 0.48×e^(−0.96s/h))
- 1
Collect the inputs
Trace width (mil) = 6; Trace thickness (mil, copper weight) = 1.4; Dielectric height to reference plane (mil) = 4; Edge-to-edge trace spacing (mil) = 6; Dielectric constant (εr) = 4.3
- 2
Apply the formula
Z0 (single-ended, IPC-2141 approx) = 87/√(εr+1.41) × ln(5.98h/(0.8w+t)); Zdiff ≈ 2×Z0×(1 − 0.48×e^(−0.96s/h))
- 3
Result
Differential impedance = 87.1338 Ω
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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