When designing or sourcing PCBs, understanding the weight per square inch is more than just a technical curiosity—it’s critical for performance, cost estimation, and logistics. In this article, we compare the most common copper weights—1oz, 2oz, and 3oz—in terms of physical weight, application suitability, and impact on pricing.
1. Understanding Copper Weight in PCBs
Copper weight in PCBs refers to the thickness of the copper layer, traditionally measured in ounces per square foot (oz/ft²). Here’s how it breaks down:
- 1oz copper = ~35µm thickness
- 2oz copper = ~70µm thickness
- 3oz copper = ~105µm thickness
This means 1oz of copper spread over 1 square foot weighs 28.35 grams. When calculating PCB weight per square inch, this value is adjusted based on the area and the copper thickness.
2. How to Calculate PCB Weight per Square Inch
Formula:
Weight (g) = Area (in²) × Copper Thickness (µm) × Copper Density
Copper Density = 8.96 g/cm³
1 inch = 2.54 cm
Let’s simplify this:
| Copper Weight | Approx. Weight per Square Inch |
| 1oz | ~1.25 grams/in² |
| 2oz | ~2.50 grams/in² |
| 3oz | ~3.75 grams/in² |
Note: These values vary slightly based on plating, surface finish, and board thickness.
3. Comparison Table: 1oz vs 2oz vs 3oz PCB Weight per Square Inch
| Copper Weight | Thickness (µm) | Weight/in² (approx.) | Best For |
| 1oz | 35µm | 1.25g | Consumer electronics, general-purpose PCBs |
| 2oz | 70µm | 2.5g | Power modules, automotive electronics |
| 3oz | 105µm | 3.75g | High-current, heat-dissipating applications |
4. Impact of Copper Weight on PCB Cost
Heavier copper increases both material usage and processing difficulty. Below is a price estimate for standard 2-layer FR4 PCBs (size: 100mm x 100mm):
- 1oz copper: ~$3.50–$5.00 per board
- 2oz copper: ~$5.00–$7.50 per board
- 3oz copper: ~$7.50–$10.00 per board
The cost increases with etching complexity, solder mask precision, and thermal management needs.
5. Performance Differences Based on Copper Weight
- Current Capacity: 3oz copper handles 3X more current than 1oz
- Thermal Management: Thicker copper dissipates heat better
- Mechanical Strength: More copper means stronger traces, ideal for rugged environments
However, heavy copper may reduce trace spacing and increase board size.
6. Choosing the Right Copper Weight for Your Project
Consider these key factors:
- Low-power designs: 1oz is sufficient and cost-effective
- Mid-power applications: 2oz balances performance and budget
- High-power circuits: 3oz is necessary for thermal and current control
Industry Examples:
- LED Lighting: 2oz or 3oz for heat
- Power Electronics: 3oz for high current
- IoT Devices: 1oz for compact design
7. KingSunPCB Copper PCB Capabilities
At KingSunPCB, we specialize in 1oz to 6oz copper PCBs with precise etching and high reliability. Our services include:
- Quick-turn prototyping
- Volume production
- ENIG, OSP, Immersion Silver/Gold finishes
- 100% E-test and inspection
Typical pricing for 100x100mm, 2-layer PCBs:
- 1oz: From $3.50/pcs
- 2oz: From $5.20/pcs
- 3oz: From $7.80/pcs
We provide free DFM checks, engineering support, and worldwide shipping.
8. Conclusion
Choosing the right copper weight directly affects the functionality, durability, and cost of your PCB. Whether you’re building a power-hungry device or a compact wearable, understanding PCB weight per square inch helps you make informed decisions.
Need a custom quote or technical advice?
Contact KingSunPCB today for expert support and competitive pricing on all copper weight options.