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Contact & Quotation

  • Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
  • Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Drag & Drop Files, Choose Files to Upload You can upload up to 3 files.

Notes:
For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.

Copper Weight/Thickness Converter - PCBsync

Copper Weight/Thickness Converter

PCBsync Engineering Tools
Unit Conversion
Quick Select
Ounces per sq ft
1.000 oz/ft²
Micrometers
35.00 µm
Millimeters
0.0350 mm
Mils (thousandths inch)
1.378 mils
Inches
0.001378 in
Grams per sq meter
305.2 g/m²
½ oz
18 µm
1 oz
35 µm
2 oz
70 µm
3 oz
105 µm
4 oz
140 µm
Electrical Properties
Sheet Resistance
0.49 mΩ/□
Per square at 20°C
Conductance
2.04 S/□
Siemens per square
Skin Depth @ 100MHz
6.6 µm
Full thickness used
Skin Depth @ 1GHz
2.1 µm
Surface conduction only
Weight
305 g/m²
Copper density: 8.96 g/cm³
Est. Current (1mm trace)
2.5 A
10°C rise, external layer
Typical Applications
1 oz (35µm) — Standard thickness for most PCBs. Suitable for signal traces, moderate power, and general-purpose circuits. Good balance of cost, manufacturability, and performance.
Weight µm mils mm Use Case
Conversion Reference
1 oz/ft² copper = 35 µm = 1.378 mils = 0.035 mm. Based on copper density of 8.96 g/cm³. The "oz" rating refers to the weight of copper spread over 1 square foot of area.

Understanding Copper Weight in PCB Design

Copper thickness on PCBs is traditionally specified by weight per unit area (oz/ft²) rather than direct thickness. This convention dates back to the copper foil manufacturing process. One ounce of copper spread evenly over one square foot yields a thickness of approximately 35 micrometers (1.37 mils).

Thickness (µm) = Weight (oz/ft²) × 35

Thickness (mils) = Weight (oz/ft²) × 1.378

1 oz/ft² = 305.15 g/m² = 35 µm = 1.378 mils

The relationship comes from copper's density (8.96 g/cm³). When 1 oz (28.35g) of copper is spread over 1 ft² (929 cm²), the resulting thickness is 28.35g ÷ (8.96 g/cm³ × 929 cm²) ≈ 0.0035 cm = 35 µm.

Standard Copper Weights
  • ¼ oz (9µm) — Ultra-fine pitch, HDI
  • ½ oz (18µm) — Fine-pitch BGAs, HDI
  • 1 oz (35µm) — Standard, most common
  • 2 oz (70µm) — Power, high current
  • 3-4 oz — Heavy power, automotive
  • 6-10 oz — Extreme power, busbars
Current Capacity Factors
  • Thicker copper = higher current capacity
  • External layers cool better than internal
  • Current capacity ∝ √(copper thickness)
  • Temperature rise is the limiting factor
  • Use IPC-2152 for accurate calculations
Manufacturing Considerations
  • Heavy copper requires wider trace spacing
  • Etching undercut increases with thickness
  • Minimum trace width increases with oz
  • Cost increases significantly above 2oz
  • Plating adds ~25µm to base foil
High-Frequency Effects
  • Skin effect limits effective thickness
  • At 1GHz, only ~2µm conducts current
  • Surface roughness affects loss
  • Thicker copper doesn't help at RF
  • Consider ENIG or immersion silver

Design Tip: For most digital and mixed-signal designs, 1 oz copper provides an excellent balance of performance, cost, and manufacturability. Reserve 2+ oz copper for power sections, high-current traces, or thermal management. For fine-pitch components (0.4mm BGA), consider ½ oz starting copper with plated finish.

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Contact Sales & After-Sales Service

Contact & Quotation

  • Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.

  • Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.

Drag & Drop Files, Choose Files to Upload You can upload up to 3 files.

Notes:
For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.