PCB via sizing determines pad diameter, annular ring width, and aspect ratio for drilled holes in printed circuit boards. Correct via dimensions ensure reliable plating, proper IPC-2221 compliance, and high manufacturing yield with your chosen PCB fab.
Via Parameters
Typical: 0.1–0.15mm (4–6mil). Min IPC Class A: 0.05mm
Enter drill size and annular ring to calculate.
Standard Via Size Reference
| Type | Drill (mm) | Pad (mm) | Drill (mil) | Pad (mil) | Use |
|---|---|---|---|---|---|
| Microvia (HDI) | 0.10 | 0.30 | 4 | 12 | BGA fanout, HDI |
| Small signal | 0.20 | 0.50 | 8 | 20 | Dense PCB |
| Standard | 0.30 | 0.60 | 12 | 24 | Most hobbyist PCBs |
| General | 0.40 | 0.80 | 16 | 32 | Standard design |
| Power via | 0.80 | 1.40 | 31 | 55 | Power/ground planes |
How to Use the PCB Via Size Calculator
This PCB via calculator computes minimum pad diameter, aspect ratio, and IPC compliance for your drill size and board thickness. Enter values in mm or mil — the most common units in PCB design tools.
Via Design Formulas
Pad Diameter = Drill Size + (2 × Annular Ring). Aspect Ratio = Board Thickness / Drill Diameter. For a 1.6mm board with 0.3mm drill: aspect ratio = 5.33:1. Keep aspect ratio below 10:1 for reliable copper plating through the hole during PCB manufacturing.
Manufacturer Capabilities
Most standard PCB fabs (JLCPCB, PCBWay, OSHPark) support 0.3mm drill minimum and 0.6mm pad. Advanced fabs offer 0.15mm drill. Laser drilled microvias go down to 0.1mm. Always check your fab's DRC rules file before finalizing your design — their checked capabilities may be tighter than IPC minimums.
Thermal Vias
Thermal vias under power components drain heat to inner copper planes. Use 0.3–0.5mm drill in a grid pattern under the thermal pad. Fill them with solder or use via-in-pad with filled and capped vias (more expensive). Typical pitch: 1.0mm grid with 10–20 vias per cm².
FAQ
Is this PCB via calculator free?
Yes, completely free. Calculate via pad sizes and aspect ratios without any account or payment.
Is my data private?
All calculations run in your browser. No data is sent to any server.
What is the minimum annular ring for a PCB via?
IPC-2221 Class A (consumer) requires 0.05mm minimum annular ring. Class B (industrial) requires 0.05mm. Class C (aerospace/military) requires 0.075mm. Most PCB manufacturers recommend 0.1–0.15mm annular ring for reliable manufacturing yields.
What is via aspect ratio?
Aspect ratio = board thickness / drill diameter. A 1.6mm board with a 0.3mm drill has an aspect ratio of 5.3:1. Most PCB manufacturers prefer aspect ratios below 10:1 for reliable plating. High aspect ratios make it difficult to plate copper uniformly through the hole.
What is the smallest via drill size I can manufacture?
Standard PCB manufacturers support 0.3mm (12mil) drill. Advanced/specialty manufacturers go down to 0.1mm. Laser drilled microvias (used in HDI boards) can be 0.1mm or smaller. Most hobbyist PCB services have a 0.3mm minimum.
What is the difference between through-hole, blind, and buried vias?
Through-hole vias connect all copper layers, penetrating the entire board thickness. Blind vias connect outer layers to inner layers but don't penetrate all the way through. Buried vias connect only inner layers. Blind and buried vias require more expensive multi-lamination PCB processes.
What is a pad diameter formula?
Minimum pad diameter = drill size + (2 × annular ring). For a 0.3mm drill with 0.15mm annular ring: pad = 0.3 + (2 × 0.15) = 0.6mm. Add manufacturing tolerance (typically 0.05–0.1mm) for the final spec. Always check your PCB manufacturer's DRC rules.