This PCB crosstalk calculator estimates the coupling between two adjacent microstrip traces from their spacing and the dielectric height. Enter both values above for an estimate.
Estimate
Coupling k ≈ 1 ÷ (1 + (s ÷ h)²)
The 3W rule — edge spacing of at least three trace widths — typically drops crosstalk to about 1%.
Example
s = 0.3 mm, h = 0.15 mm (s/h = 2): k ≈ 1 ÷ (1 + 4) = 0.2 (20%). Widen the spacing to cut it sharply.
Related calculators
Frequently Asked Questions
How do I reduce PCB crosstalk?
Increase the spacing between traces. The 3W rule — spacing of three trace widths — cuts crosstalk to roughly 1%.
What causes crosstalk?
Capacitive and inductive coupling between adjacent traces, which grows as they run closer and longer in parallel.
Does a ground plane help?
Yes. A close return plane and guard traces reduce coupling and confine the fields.