PCB Trace Width Calculator – Accurate PCB Design Made Easy

About Airbuddy Aerospace Pvt. Ltd.

Airbuddy Aerospace Pvt. Ltd. is an innovative engineering company that specializes in the design and manufacturing of custom-designed motors with patented Printed Winding Technology. This technology uses copper traces on a PCB to replace traditional wire windings, resulting in motors that are highly efficient, lightweight, and power-dense.

The company focuses on providing tailored motor solutions for a range of applications, including Unmanned Aerial Vehicles (UAVs), Electric Vehicles (EVs), and robotics. They emphasize a rapid design-to-delivery process and a commitment to sustainability by using less copper and producing quieter, lighter motors.

Website: www.airbuddy.in

Introduction

In PCB (Printed Circuit Board) design, trace width is one of the most critical factors that determines a board's reliability, thermal performance, and electrical efficiency. Choosing the wrong trace width can lead to overheating, voltage drops, or even circuit failure.

To address this, I have developed a web-based PCB Trace Width Calculator, This tool simplifies the process by allowing engineers, makers, and students to calculate the ideal trace width based on current, copper thickness, and temperature rise — all using IPC-2221 standard formulas.

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Why Trace Width Calculation is Important

A PCB trace acts as a conductor, similar to a wire, and must carry current without excessive heating.

• Too narrow → high resistance, more heat, possible damage.

• Too wide → wasted PCB space and cost.

The industry uses IPC-2221 (Generic Standard on Printed Board Design) as the guideline for determining trace width for both internal and external layers.

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Core Formula (IPC-2221 Standard)

For external layers:

$$W= \left( \frac{I}{k \cdot (\Delta T)^b} \right)^{\frac{1}{c}}$$

Where:

• W = Trace width (mil)

• I = Current (A)

• ΔT = Allowed temperature rise (°C)

• k=0.048, b=0.44, c=0.725 (external layer constants)

For internal layers:

$$W=\left( \frac{I}{k \cdot (\Delta T)^b} \right)^{\frac{1}{c}}$$

Where:

• k=0.024, b=0.44, c=0.725 (internal layer constants)

Additionally, resistance and voltage drop are calculated as:

$$R = \rho \cdot \frac{L}{A}$$

$$V_{\text{drop}} = I \cdot R$$

$$P_{\text{loss}} = I^2 \cdot R$$

Where:

• ρ = resistivity of copper (1.724 × 10⁻⁶ Ω·cm)

• L = trace length (cm)

• A = cross-sectional area (cm²)

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Features of My PCB Trace Width Calculator

✔ Web-based & responsive – Works in any browser
✔ Supports multiple units – mil, mm, oz/ft², µm
✔ Separate calculations for internal & external layers
✔ Outputs width in mil, mm, and µm
✔ Calculates resistance, voltage drop, and power loss
✔ Follows IPC-2221 standard formulas

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How It Works – UI Walkthrough

1. Enter current (A) – Load your circuit’s current requirement.

2. Set ambient temperature & rise limit – Safety margin for thermal stability.

3. Provide trace length & copper thickness – Based on your PCB specs.

4. Select units – The calculator automatically converts between mil, mm, and µm.

5. Get instant results – Ideal trace width, resistance, voltage drop, and power loss.

💻 live demo: https://pcb-trace.netlify.app/

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Sample Code Snippet

Here’s a simplified example from the project that calculates external layer width:

function calculateExternalWidth(current, tempRise) {
    const k = 0.048;
    const b = 0.44;
    const c = 0.725;
    return Math.pow(current / (k * Math.pow(tempRise, b)), 1 / c);
}

// Example: 5A current, 10°C rise
let widthMil = calculateExternalWidth(5, 10);
console.log(`Required external trace width: ${widthMil.toFixed(2)} mil`);

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Example Output

Inputs:

• Current: 15 A

• Ambient Temperature: 30°C

• Temperature Rise: 30°C

• Length: 10 in

• Copper Thickness: 40 oz/ft²

Results:

• Internal Layer Width: 16.54 mil (0.420 mm)

• External Layer Width: 9.35 mil (0.237 mm)

• Resistance: 0.00748 Ω

• Voltage Drop: 0.1122 V

• Power Loss: 1.68 W

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Conclusion

The PCB Trace Width Calculator helps engineers, hobbyists, and students design safer, more efficient PCBs by applying proven IPC-2221 standards in an intuitive interface.

💻 live demo: https://pcb-trace.netlify.app/

Future improvements may include:

• Adding multi-layer PCB support

• Integration with KiCad or Eagle as a plugin

• Automatic temperature rise estimation based on load

• 3D visualization

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📬 Contact

For inquiries, collaborations, or feedback related to this project, please reach out:

Name: Ajit Kumar
Email: ajit.info999@gmail.com
LinkedIn: linkedin.com/in/ajit421