Free Engineering Tool
Via Current & Temperature Rise Calculator
Find the temperature rise of a plated through-hole via for a given current — or the maximum current for a given rise limit. Based on the IPC-2221 ampacity model applied to the via barrel cross-section.
Via Current Calculator
Two modes: enter current to find temperature rise, or enter a rise limit to find maximum current per via.
Design Inputs
Standard 1.6mm board ≈ 62 mil
Results
Temperature Rise
Cross-Section
34.6 mil²
Inner Diameter
10 mil
Resistance
1.23 mΩ
V Drop
1.23 mV
Power Loss
1.23 mW
Per IPC-2221 for plated through-hole vias. The model treats the via barrel as a hollow copper cylinder with uniform plating. Real-world current capacity also depends on pad/land thermal relief, adjacent copper planes, reflow temperatures and via fill status.
Need high-current vias? We fabricate heavy-copper boards (up to 6 oz) with controlled via plating.
Get Instant QuoteThe Method
How via current capacity is calculated
A plated through-hole via is a hollow copper cylinder. The calculator finds its cross-sectional area from the drill diameter and plating thickness, then applies the IPC-2221 temperature-rise relationship — the same model used for traces.
1. Via barrel cross-section
A = π/4 × (D² - d²)
d = D - 2t
D = drill diameter
t = plating thickness (1 mil IPC Class 2)2. Temperature rise (IPC-2221)
ΔT = (I / (k × A^0.725))^(1/0.44)
k = 0.048 (external)
A in mil², I in amps, ΔT in °CFAQ
Via current capacity, answered
How much current can a single PCB via carry?
It depends on drill diameter, plating thickness, and allowable temperature rise. A typical 12 mil drill with 1 mil plating carries roughly 1 A at 10°C rise per IPC-2221. Larger drills or thicker plating increase capacity; parallel vias share the current for higher loads.
What plating thickness should I assume?
IPC Class 2 requires a minimum 1 mil (25 µm) average copper plating. IPC Class 3 requires 1 mil minimum with tighter distribution. This calculator defaults to 1 mil — the most common production value.
When should I use parallel vias?
Use parallel vias when a single via exceeds 10°C rise, when voltage drop is too high for your PDN, or when you need mechanical redundancy. Multiple smaller vias often outperform one large via.
Does via fill affect current capacity?
Copper-filled vias have significantly higher capacity since the entire cross-section is conductive. This calculator models standard plated (hollow) vias. For filled vias, the effective area is the full drill circle.
Need high-current vias fabricated?
Heavy copper, controlled plating thickness, via-in-pad — engineer-reviewed, 1-piece MOQ, 99% on-time.