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Free PCB Via Current & Temperature Calculator Electronics & RF
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Free PCB Via Current & Temperature Calculator

Calculate plated through-hole via ampacity, DC resistance, voltage drop, and Joule heating temperature rise based on IPC-2152 standards.

⚡ Via Geometry & Substrate Specs

1 mil = 0.0254 mm (12 mil ≈ 0.3mm)
IPC Class 2 min = 0.8 mil (20µm)
Standard 1.6mm FR4 ≈ 62.9 mils
Continuous DC/RMS load per via

📊 Via Electrical & Thermal Results

Via DC Resistance 1.12 mΩ Milliohms (mΩ)
Current Capacity (@ ΔT) 1.82 A IPC-2152 limit
Copper Barrel Area: 40.8 mils²
Voltage Drop Across Via: 1.68 mV
Joule Power Dissipation: 2.52 mW
Estimated Temp Rise (ΔT): +10.2°C
Total Operating Temperature: 35.2°C
Parallel Vias Recommended: 1 Via Sufficient
✅ Thermal state: Safe within limits. Low thermal stress.

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Physics of Plated Through-Hole (PTH) Vias

In high-power PCB layouts (such as motor drives, buck-boost switchers, and Li-ion battery management systems), plated through-hole vias act as localized electrical and thermal bottlenecks. A common layout mistake is routing a wide 100-mil surface trace carrying 5 Amps into a single default 12-mil via drill.

Via Barrel Cross-Sectional Area Formula

A via is a hollow copper cylinder. The conductor cross-sectional area (A) is calculated as:

A = π × (d_outer² - d_drill²) / 4 ≈ π × (d_drill + t_plating) × t_plating

For a standard 12 mil (0.3 mm) finished hole with 1 mil (25.4 µm) copper barrel plating, the cross-sectional area is approximately 40.8 mils² (0.026 mm²), which is equivalent to a tiny 30 AWG wire!

Via Stitching & Thermal Relieving

When current demands exceed 1.5 Amps, engineering best practice is via stitching. Placing 2 to 4 parallel vias spaced 2 to 3 diameters apart slashes DC loop resistance, minimizes parasitic via inductance (ESL), and spreads localized thermal flux into power and ground planes.

Frequently Asked Questions

How much continuous current can a standard 12 mil via carry?

With standard 1.0 mil (25 µm) copper plating, a 12 mil via can safely carry about 1.5 to 1.8 Amps for a 10°C to 15°C temperature rise. Exceeding 2 Amps through a single standard via causes significant localized heating.

What is the DC resistance of a standard FR4 through-hole via?

A 12 mil drill via through a standard 63 mil (1.6 mm) thick FR4 PCB has a DC resistance of approximately 1.1 to 1.3 milliohms (mΩ). While small, high currents cause noticeable I²R losses.

Does filling or tenting vias increase their current carrying capacity?

Solder mask tenting does not increase ampacity. Solid solder fill during wave or reflow soldering slightly decreases resistance, but lead-free solder has only ~10% the electrical conductivity of copper. Adding extra parallel copper vias is vastly superior.

What is the difference between IPC-2221 and IPC-2152 for via calculations?

IPC-2221 used conservative empirical data from 1950s single-layer boards in still air. IPC-2152 uses modern multi-layer boards with internal copper planes acting as heat sinks, providing much more accurate real-world current ratings.