How much current can a via on a PCB carry? This is a question the designer has to answer when designing circuits that may be current intensive such as DC – DC converters, regulators, power amplifiers, etc. One can use a very detailed analysis to do this, or use a rule of thumb that says, that the current carrying capability of a via with an internal diameter of X, is approximately 3 times the current carrying capability of a trace with the same width X.