PCB Trace Current Capacity Calculator

Current Capacity Formula:

\[ I = (k \times \Delta T^{0.44}) \times (A)^{0.725} \]

Current Capacity (I): amps

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is a PCB Trace Current Capacity Calculator?

Definition: This calculator estimates the maximum current a PCB trace can handle based on temperature rise, cross-sectional area, and material properties.

Purpose: It helps electronics designers ensure their PCB traces can safely carry required currents without excessive heating.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ I = (k \times \Delta T^{0.44}) \times (A)^{0.725} \]

Where:

\( I \) — Current capacity (amps)
\( \Delta T \) — Temperature rise above ambient (°C)
\( A \) — Cross-sectional area (m²)
\( k \) — Material constant (0.048 for copper)

Explanation: The formula accounts for heat dissipation through the PCB trace based on its material and dimensions.

3. Importance of Current Capacity Calculation

Details: Proper current capacity estimation prevents trace overheating, ensures reliability, and meets safety standards.

4. Using the Calculator

Tips: Enter the desired temperature rise, trace cross-sectional area, and material constant (default 0.048 for copper). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical temperature rise limit?
A: Common limits are 10-20°C for general designs, up to 30°C for high-reliability applications.

Q2: How do I calculate cross-sectional area?
A: Multiply trace width by thickness (e.g., 0.2mm × 0.035mm = 0.000007 m²).

Q3: When would I change the material constant?
A: Use 0.024 for external layers or 0.048 for internal layers (typical values for copper).

Q4: Does this account for ambient temperature?
A: ΔT is the rise above ambient, so ambient must be considered separately.

Q5: What safety margin should I use?
A: A 20-30% derating is common practice for critical applications.