Calculate PCB trace impedance for microstrip, stripline, and coplanar waveguide structures.
| Application | Impedance | Notes |
|---|---|---|
| USB 2.0 | 90 Ω ±10% | Differential pair |
| USB 3.0 | 90 Ω ±10% | Differential pair |
| HDMI | 100 Ω ±10% | Differential pair |
| Ethernet | 100 Ω ±10% | Differential pair |
| PCIe | 85 Ω ±10% | Differential pair |
| RF 50Ω | 50 Ω ±5% | Single-ended |
This calculator uses IPC-2141 standard formulas to estimate characteristic impedance based on trace geometry and material properties.
A trace on the outer layer with a ground plane below. Most common for high-speed signals.
A trace buried between two ground planes. Better shielding but higher loss.
A trace with ground planes on both sides on the same layer. Good for RF and tight spaces.
FR-4 typically has an Er of 4.2-4.8 at 1 MHz. At higher frequencies (1 GHz+), use 4.0-4.3. Check your laminate datasheet for exact values.
PCB manufacturers use 2D/3D field solvers which account for more variables like etch factor, solder mask, and actual material properties. These calculators provide estimates - always verify with your manufacturer.
Differential impedance is approximately 2× single-ended impedance minus coupling factor. For USB (90Ω differential), target ~45Ω single-ended with appropriate spacing.