⚡ Crosstalk Calculator
Estimate inductive and capacitive crosstalk between parallel PCB traces (microstrip).

Topology

Microstrip: traces on the outer PCB layer above a ground plane.
GND Aggressor Victim H S
$$K_B = \tfrac{1}{4}\!\left(\dfrac{C_m}{C_0}+\dfrac{L_m}{L_0}\right) \qquad K_F = \tfrac{1}{2}\!\left(\dfrac{C_m}{C_0}-\dfrac{L_m}{L_0}\right)$$

Backward (near-end) and forward (far-end) crosstalk coefficients. Mutual C and L are estimated from Hammerstad–Jensen closed-form expressions. Results are approximate — use EM simulation for precision work.

FR4 ≈ 4.3 at 1 GHz

Peak-to-peak voltage of aggressor signal

⚠ Please enter trace width, spacing, and dielectric height.

Results

3W Rule Check

Enter trace width and spacing to see the 3W rule check.

About Crosstalk

Backward (near-end) crosstalk KB appears at the source end of the victim trace and grows with coupled length until the line delay exceeds half the rise time, after which it saturates. Forward (far-end) crosstalk KF appears at the far end of the victim and increases proportionally with coupled length.

In a stripline (symmetric), forward crosstalk is near-zero because the inductive and capacitive components cancel. In microstrip they do not cancel, leading to non-zero forward crosstalk. The 3W rule (centre-to-centre spacing ≥ 3× trace width) reduces EMI radiation and coupling to below −10 dB.