Wire Gauge Calculator
Calculate the recommended AWG wire gauge based on current, distance, and acceptable voltage drop.
Supports feet and meters.
Recommended Wire Gauge
Wire Gauge Selection is based on keeping voltage drop within acceptable limits over the wire run distance.
Voltage Drop Formula:
V_drop = (2 × Length × Current × Resistance_per_unit) / 1000
The factor of 2 accounts for the round-trip (positive and negative conductors).
Unit handling:
- Feet: Uses resistance in ohms per 1,000 feet (standard AWG tables)
- Meters: Converts to feet internally (1 m = 3.281 ft)
AWG resistance values (copper, at 20°C):
| AWG | Ω/1000ft | Max Amps |
|---|---|---|
| 14 | 2.525 | 15A |
| 12 | 1.588 | 20A |
| 10 | 0.999 | 30A |
| 8 | 0.628 | 40A |
| 6 | 0.395 | 55A |
| 4 | 0.249 | 70A |
| 2 | 0.156 | 95A |
General rule: Keep voltage drop under 3% for branch circuits and 5% total for feeder + branch combined.