Electrical Cable Size Calculator

Calculate the appropriate cable size for your electrical installation

⚠️ Important: This calculator is for reference only. Always consult a licensed electrician for final decisions.

Input Parameters

Calculation Results

Enter parameters and click "Calculate" to see results

Cable Ampacity Reference Table

AWG/kcmil mm² Copper (A) Aluminum (A)
14 AWG 2.5 20 -
12 AWG 4 25 20
10 AWG 6 35 25
8 AWG 10 50 40
6 AWG 16 65 50
4 AWG 25 85 65
2 AWG 35 115 90
1 AWG 50 130 100
1/0 AWG 70 150 120
2/0 AWG 95 175 135
3/0 AWG 120 200 155
4/0 AWG 150 230 180
250 kcmil 185 255 205
300 kcmil 240 285 230

* Ampacity values based on 75°C insulation, single cable in air at 30°C ambient temperature

How to Use This Calculator

1. Enter System Voltage

Input your system voltage (e.g., 120V for residential, 240V for appliances, 480V for industrial)

2. Enter Load Current

Enter the current draw of your electrical load in Amperes. Use the nameplate rating or calculated load current.

3. Select Phase Configuration

Choose single-phase for most residential applications or 3-phase for industrial/commercial installations.

4. Choose Cable Material

Copper offers better conductivity but is more expensive. Aluminum is lighter and cheaper but requires larger sizes.

5. Set Ambient Temperature

Higher ambient temperatures reduce cable capacity. Default is 30°C (86°F).

6. Enter Cable Distance

The length of the cable run affects voltage drop. Longer distances require larger cables.

⚠️ Safety Warnings

  • Always consult a licensed electrician for actual installations
  • Use appropriate cable insulation type for your application
  • Consider derating factors for bundled cables or conduit installation
  • Ensure proper grounding and overcurrent protection
  • Follow local electrical codes and standards (NEC, IEC, etc.)
  • This calculator is for estimation purposes only