Cable Gauge Calculator — AWG for Speaker Cables

Using the common 5% rule (cable resistance no more than 5% of the speaker impedance) at 8 ohms, this calculator returns: 18 AWG up to about 9.5m; 16 AWG to 15m; 14 AWG to 24m; 12 AWG to 38m. For a more conservative real-world install (keeping cable resistance to roughly 2-3% of the impedance) go one gauge thicker — e.g. 14 AWG up to 15m, 12 AWG to 20m, 10 AWG to 30m. For 4-ohm loads, go one gauge thicker again, since the same cable resistance is a larger fraction of a lower impedance.

AWG (American Wire Gauge) is a standardised system for wire sizes. Lower numbers mean thicker wire. Each 3-gauge reduction doubles the cross-sectional area and halves the resistance. Common speaker cable gauges are 12-18 AWG.

Yes, thicker cable always reduces loss. The only downsides are cost, weight and flexibility. There is no electrical downside to using thicker cable. However, beyond a certain point the improvement is negligible.

For speaker cables, gauge (and therefore resistance) is by far the most important factor. The conductor material (oxygen-free copper vs standard copper) makes a negligible difference at audio frequencies. Good insulation and durable connectors are more important than exotic materials.