PCB Via Current Calculator
Estimate PCB via current capacity, via barrel resistance, voltage drop and required number of vias from drill size, plating thickness, PCB thickness and allowable temperature rise.
🧩 PCB Rule: A via behaves like a tiny copper tube. Bigger drill, thicker plating and multiple parallel vias reduce resistance and heating. Use this with the PCB Trace Width Calculator, PCB Trace Impedance Calculator, MOSFET Power Loss Calculator and Voltage Regulator Heat Sink Calculator.
🧩 Via Barrel → Copper Area → Current / Resistance
Finished Drill Diameter
Copper Plating Thickness
PCB Thickness
Allowable Temp Rise
Via Count
Estimate Type
This is an engineering estimate, not a replacement for IPC-2152 testing, thermal simulation, or manufacturer design rules.
Presets:
Load Current
Drill Diameter
Plating Thickness
PCB Thickness
Temp Rise
Safety Margin
Use via arrays for high current paths, especially between power planes, MOSFET drains, regulators, connectors and battery traces.
Load presets:
Current Through Via Group
Via Count
Drill Diameter
Plating Thickness
PCB Thickness
Copper Temp
Resistance is based on the via barrel as a plated copper cylinder. Multiple identical vias in parallel divide the total resistance approximately by via count.
Examples:
📐 Formula Reference
Via Barrel Area
A ≈ π × drill diameter × plating thickness
Via Resistance
R = ρ × board thickness ÷ copper area
Voltage Drop
Vdrop = I × R
Power Loss
P = I² × R
📋 Quick Reference
Typical Via Geometry
Small signal via0.20–0.30mm
Common via0.30–0.50mm
Power via0.50–1.00mm+
Plating Thickness
Standard20–25µm
Heavy plating35µm+
1 oz equivalent≈35µm
Design Practice
High currentuse array
Thermal viamany small
Power planesmultiple vias
📚 Engineering Notes
Via current is geometry dependentDrill size, plating thickness and board thickness all matter. A wider plated barrel has lower resistance and lower heating.
Use multiple vias for powerFor regulators, MOSFETs, connectors and battery paths, multiple vias in parallel are usually safer than relying on one via.
Temperature rise is not exactReal via temperature depends on copper planes, airflow, solder fill, nearby heat sources and board stackup. Treat this as a practical estimate.
Resistance matters at high currentEven a few milliohms can create voltage drop and heat when current is high.
What is a PCB Via Current Calculator?
A PCB via current calculator estimates how much current a plated through-hole via can carry and how much resistance, voltage drop and heat it may create. It is useful for power routing, DC-DC converters, MOSFET boards, battery circuits and high-current connectors.
Why use multiple vias?
Multiple vias in parallel reduce the current per via and reduce the equivalent resistance. This improves reliability and lowers temperature rise in power paths.
Important limitation
This calculator is an estimate. For production PCB design, confirm the result with your PCB manufacturer, stackup, plating specification, IPC guidance, thermal simulation or testing.
❓ Frequently Asked Questions
It depends on plating thickness, board thickness and allowed temperature rise. A 0.3mm via with normal plating is often suitable for modest current, but high-current paths should use several vias in parallel.
Both matter because via barrel copper area is roughly proportional to drill diameter times plating thickness. Increasing either one lowers resistance and improves current capacity.
Use the copper barrel cross-sectional area and board thickness: R = copper resistivity × via length ÷ copper area. This calculator does that automatically.
Solder filling can help somewhat, but copper has much better conductivity than solder. The better solution is usually larger vias, thicker plating, more vias, or copper planes.
Use enough vias so each via carries a comfortable current with margin. For several amps, a via array is usually preferred over a single via.