Wire size calculator

What are you sizing for?
A
ft

From the panel to the load, not there and back

Voltage
Conductor
Termination rating
Result
10 AWG copper

The run is long: ampacity alone allows 12 AWG, but a larger wire keeps the drop within 3%.

Breaker
20 A
Voltage drop
2.5 V (2.1%)
Volts at the load
117.5 V
Ground wire
10 AWG copper

How it is calculated

  1. Breaker: 20 A rounded up to a standard size = 20 A.
  2. Smallest copper conductor rated for 20 A at 75 °C: 12 AWG.
  3. Drop = 2 × K × 20 A × 50 ft ÷ 10,380 cmil = 2.49 V, target 3% of 120 V.
Panel20 A120 V10 AWG copper50 ft one wayLoad117.5 V

Wire size calculator by Calculate.diy.For planning only; check local code.