Pad Size Calculator
IPC-2221 Compliant • Annular Ring Calculator
Calculate the optimal pad size for through-hole components, vias, and SMD pads. Ensure adequate annular ring for reliable manufacturing.
Pad Parameters
Pad Size Results
Common Pad Size Reference
| Hole Size | Min Annular Ring | Recommended Pad | Typical Use |
|---|---|---|---|
| 0.3mm | 0.05mm | 0.4mm | Microvia |
| 0.5mm | 0.10mm | 0.7mm | Via |
| 0.8mm | 0.15mm | 1.1mm | TH Component |
| 1.0mm | 0.15mm | 1.3mm | TH Component |
| 1.2mm | 0.20mm | 1.6mm | Power Pin |
*Minimum values per IPC-2221. Add extra margin for manufacturability.
Understanding Annular Ring
What is Annular Ring?
The annular ring is the copper area between the edge of the drilled hole and the outer edge of the pad. It's critical for:
- •Reliable electrical connection
- •Mechanical strength of the joint
- •Manufacturing tolerance compensation
- •Solder joint quality
IPC Class Requirements
Pad Design Best Practices
Drill Tolerance
Account for drilling tolerance (typically ±0.05mm) when calculating pad size. Add this to your minimum annular ring requirement.
Pad Shape Selection
Use circular pads for standard vias, oblong for routing flexibility, and square pads only for pin 1 identification on connectors.
Thermal Considerations
Large pads connected to planes need thermal relief for proper soldering. Use our thermal relief calculator for optimal spoke design.
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Pad Size FAQ
What is the minimum pad size for a 0.8mm hole?
For IPC Class 2, use at least 1.0mm pad (0.1mm annular ring per side). For manufacturing safety, 1.1-1.2mm is recommended.
Should I use larger pads for better soldering?
Larger pads provide more surface area for solder but require more board space. Balance solderability needs with routing density requirements.
What is breakout in PCB manufacturing?
Breakout occurs when the drilled hole is misaligned with the pad, reducing or eliminating the annular ring. Adequate pad size prevents this.
How do I calculate pad size for oval/oblong pads?
Use the minimum dimension equal to hole + 2× annular ring. The elongated dimension can be 1.5-2× the minimum for routing flexibility.
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