LED Screen Capacity Calculation Guide: Sending Cards, Receiver Cards, and Pixel Load

If you want a stable LED display system, you must size your sending card ports and receiver cards correctly. Undersizing leads to black screens or flickering; oversizing wastes budget.

This guide gives you a practical, engineering-grade method to calculate everything accurately.

1. Step One: Calculate Total Screen Pixels

Always start here. Every decision depends on total pixel count.

Formula

Total Pixels = Horizontal Pixels × Vertical Pixels

Break it down further:

• Horizontal Pixels = Module Width (pixels) × Number of Modules (horizontal)
• Vertical Pixels = Module Height (pixels) × Number of Modules (vertical)

Example

• Module: 128 × 64
• Layout: 10 (W) × 8 (H)

Calculation:

• Horizontal = 128 × 10 = 1280
• Vertical = 64 × 8 = 512

Total Pixels = 1280 × 512 = 655,360 pixels

2. Sending Card Capacity (Ethernet Port Load)

The sending card determines how many pixels your system can drive.

2.1 Theoretical Capacity per Port

• Gigabit Ethernet port (1Gbps):
  • ~655,360 pixels @ 60Hz
• 30Hz mode (if supported):
  • ~1,050,000 pixels per port

2.2 Effective Capacity (Real-World Adjustment)

Higher refresh rates consume more bandwidth, so you must apply a reduction factor.

Engineering Coefficients

Example (3840Hz)

Effective Load = 655,360 × 0.6 = 393,216 pixels per port

2.3 Total Sending Card Capacity

Total Capacity = Number of Ports × Effective Load per Port

Example

• Sending card: 4 ports
• Refresh rate: 3840Hz

Calculation:

Total = 4 × 393,216 = 1,572,864 pixels

3. Receiver Card Capacity (Per Card)

Receiver cards distribute data to LED modules. You must respect both pixel limits and dimension limits.

Common Receiver Card Specs

Dimension Constraints (Critical)

A receiver card must satisfy BOTH:

• Horizontal pixels ≤ max horizontal limit
• Vertical pixels ≤ max vertical limit

Example

• Receiver card: 256 × 128
• Module: 128 × 64

Max modules per card:

• Horizontal: 256 ÷ 128 = 2
• Vertical: 128 ÷ 64 = 2

Max load = 2 × 2 = 4 modules per receiver card

4. Full System Validation (Most Important Step)

Now verify that your entire system is balanced.

You MUST satisfy all three conditions:

1. Total Screen Pixels ≤ Sending Card Capacity

2. Pixels per Port ≤ Single Port Capacity

3. Pixels per Receiver Card ≤ Receiver Card Limit

Example Check

• Screen: 1280 × 512 = 655,360 pixels
• Refresh rate: 3840Hz
• Single port capacity: 393,216 pixels

Result:

655,360 > 393,216 → One port is NOT enough

Solution: Use 2 ports

5. Fast Engineering Rules (Field-Proven)

Use these quick rules for rapid estimation:

Sending Card (Gigabit Port)

• ~650K pixels per port @ 60Hz
• High refresh (≥3840Hz):
  → Use 60%–80% of capacity

Receiver Card

• 256 × 128 → Standard
• 512 × 256 → High-performance

Golden Rule

Always calculate total pixels first—then match ports and receiver cards accordingly

Conclusion

Accurate LED system design follows a clear hierarchy:

Pixels → Ports → Receiver Cards

If you skip this logic, you risk:

• Overloading ports → flickering, black screens
• Overloading receiver cards → partial display failure
• Poor system stability

On the other hand, if you size everything correctly, your LED display will run:

• Stable
• Efficient
• Scalable