Work out via current capacity instantly with clear inputs, formula shown and shareable results.
A via's conductor is the plated barrel, an annulus of copper whose area is pi times diameter times plating thickness. Applying the same IPC-2221 relation used for traces gives the current capacity, which is why power connections between layers use several vias in parallel rather than one.
Via capacity
barrel area = pi x d x plating thickness; current from the IPC-2221 area relation
Electrical results are planning estimates only. Verify against the applicable wiring rules (IEC 60364, BS 7671, NEC or local code) and have all installation work designed and checked by a qualified electrician.
A 0.3 mm via with 25 micron plating carries only about 1-2 A for a 20 degree rise. Power nets therefore stitch multiple vias in parallel.
Barely — capacity is set by cross-section and cooling. Length affects resistance and therefore voltage drop and local heating.