12 Volt Wire Size Calculator
Calculate proper wire size for 12V DC systems with low voltage drop analysis
Calculate 12V Wire Size
Maximum current the device will draw (amperes)
Distance from power source to device (one-way)
Recommended: 3% for LED lighting, 5% max for 12V DC
Copper preferred for 12V applications due to better conductivity
Typical: 25°C (indoor), 50°C (automotive), 70°C (engine bay)
Fixed at 12V for automotive, marine, and low-voltage applications
Wire Size Results
Actual Voltage Drop: 0.00%
System Power: 0.0 W
Material: Copper
Max Safe Current: 0.0 A
Application: No data - Enter values to calculate
⚠️ 12V DC Safety Notes
Example: LED Light Strip
Given Parameters
Application: 12V LED light strip
Current: 5 amperes
Distance: 7 meters
Voltage Drop: 3% maximum
Material: Copper wire
Calculation
A = (2 × I × ρ × L) / (V × %drop)
A = (2 × 5 × 1.68×10⁻⁸ × 7) / (12 × 0.03)
A = 1.176×10⁻⁶ / 0.36 = 3.27×10⁻⁶ m²
A = 3.27 mm² (recommended: 12 AWG)
Common 12V Wire Sizes
Current ratings for 5m run with 3% voltage drop
12V Applications
🚗 Automotive
Car accessories, lighting, radios
Typical: 14-18 AWG
⛵ Marine
Boat electronics, navigation lights
Typical: 12-16 AWG
💡 LED Lighting
Strip lights, landscape lighting
Typical: 14-18 AWG
🏠 RV/Solar
DC appliances, solar systems
Typical: 10-14 AWG
12V Wiring Tips
Keep voltage drop under 3% for optimal performance
Use copper wire for better conductivity
Consider temperature derating for hot environments
Always use proper fusing for safety
Understanding 12V DC Wire Sizing
12V DC Systems
12-volt DC systems are common in automotive, marine, RV, and low-voltage applications. Proper wire sizing is critical because low voltage systems are more sensitive to voltage drop, which can cause poor performance or equipment damage.
Key Considerations
- •Voltage drop has greater impact at 12V than higher voltages
- •Temperature affects wire resistance significantly
- •Copper preferred over aluminum for 12V applications
- •Factor of 2 accounts for positive and negative conductors
12V Wire Sizing Formula
Wire Area: A = (2 × I × ρ × L) / (V × %drop)
Voltage Drop: VD = (2 × I × ρ × L) / A
Power: P = V × I = 12 × I
Current: I = P / 12
Voltage Drop Guidelines
• 3% maximum for LED lighting and sensitive electronics
• 5% maximum for general 12V DC applications
• 2% for high-performance audio systems
• Consider starting current for motors (2-3x running current)
Common 12V Applications
🚗 Automotive Systems
Car accessories, dash cams, LED lights, aftermarket electronics. Typical wire sizes: 16-14 AWG for most accessories.
⛵ Marine Electronics
Navigation equipment, fish finders, radios, cabin lighting. Use tinned copper wire for corrosion resistance.
🏡 Solar & RV
DC appliances, LED lighting, charge controllers, inverters. Proper sizing critical for battery efficiency.