Via Current Capacity Calculator

A via is a tiny copper-plated hole drilled through a PCB (circuit board) that carries electrical current between layers — and knowing how much current it can safely handle prevents overheating and board damage. Enter your via diameter, plating thickness, and PCB thickness along with your ambient temperature and maximum temperature rise into the Via Current Capacity Calculator to find the maximum current capacity. Secondary outputs include via resistance, voltage drop, power loss, cross-sectional area, and current density.

mil

Diameter of the drilled via hole

mil

Thickness of copper plating on via walls

mil

Total thickness of PCB through which via passes

°C

Operating ambient temperature

°C

Allowable temperature rise above ambient

A

Optional: Current to verify against calculated capacity

Results

Maximum Current Capacity

--

Via Resistance

--

Voltage Drop

--

Power Loss

--

Cross Sectional Area

--

Current Density

--

More Electrical & Electronics Tools

Frequently Asked Questions

What is the IPC-2221 standard for via current capacity?

IPC-2221 is the industry standard that provides guidelines for calculating current carrying capacity of PCB conductors including vias. It uses empirical formulas based on temperature rise, cross-sectional area, and material properties.

How does via diameter affect current carrying capacity?

Larger via diameters provide more cross-sectional area for current flow, resulting in higher current carrying capacity. The relationship is proportional - doubling the diameter roughly doubles the capacity.

What temperature rise is acceptable for PCB vias?

Typical acceptable temperature rise is 10°C to 20°C above ambient. Lower temperature rise increases reliability and component lifespan, while higher rise may be acceptable for short-term operations.

How does plating thickness impact via current capacity?

Thicker copper plating increases the conductive cross-sectional area of the via wall, allowing higher current carrying capacity. Standard plating thickness ranges from 0.5 to 3 mils.

What factors limit via current carrying capacity?

The main limiting factors are cross-sectional area (via diameter and plating thickness), allowable temperature rise, PCB thickness, and copper resistivity at operating temperature.

How accurate are via current capacity calculations?

Calculations based on IPC-2221 provide good estimates for design purposes, but actual performance can vary by ±20% due to manufacturing tolerances, material variations, and environmental conditions.

When should I use multiple vias instead of a single large via?

Multiple smaller vias are often preferred when space is limited, for better thermal distribution, or when manufacturing constraints limit via size. The total current capacity is roughly the sum of individual via capacities.

What happens if a via carries more current than its rated capacity?

Exceeding current capacity can cause excessive heating, copper migration, via failure, or PCB damage. This may lead to intermittent faults that are difficult to diagnose and can compromise product reliability.