For current to transfer on a PCB without the fear of some overheating and subsequently damaging the whole board, sufficient trace width must be present. On PCBs of all sizes, there’s a simple correlation existing between the carrying capacity and the trace width.
Of importance to note though is that the carrying capacity of trace doesn’t necessarily correspond to space in the cross-section. Again, the amount of current that can be held by evidence, at maximum, is not easy to calculate, irrespective of the width of the trace.
Vias and other elements on the board can affect the carrying capacity of the current. Boards with numerous pads may experience a trace of outstanding ability. If you do not account for this factor during the soldering process, there might be some excessive cross-sectional area with the probability of transient surges occurring.
To prevent the above situations, PCB makers tend to enlarge the width of the trace or add extra solder mask to these traces. With this and plenty of other factors, you’ll realize that the price of PCBs tends to go high than expected.