What gauge speaker wire should I use?

For runs under 5m at 8 ohms: 16 AWG is fine. For 5-15m: 14 AWG. For 15-30m: 12 AWG. For longer runs or 4-ohm speakers, go one gauge thicker. Lower impedance speakers require thicker wire for the same loss percentage.

How much power loss is acceptable?

Keep power loss below 5% (about 0.45 dB). Below 2% (about 0.18 dB) is ideal. The dB figure is a voltage ratio — 20 × log10(Z / (Z + R_cable)) — so 5% maps to roughly 0.45 dB, not 0.2 dB. Losses above 10% become audible and waste amplifier power as heat in the cable. For professional installations, aim for under 0.5 dB loss.

Does speaker cable affect sound quality?

Cable resistance is the primary factor — it reduces damping factor and causes minor frequency response changes. For short runs with adequate gauge, the effect is negligible. Exotic cable materials and constructions offer no measurable benefit beyond achieving low resistance.

Why does impedance affect cable requirements?

Cable resistance forms a voltage divider with speaker impedance. A 0.5Ω cable with an 8Ω speaker loses 6% of power. The same cable with a 4Ω speaker loses 11%. Lower impedance speakers always need thicker cables for the same loss percentage.

AudioCalcs

Speaker Wire Calculator — Cable Gauge & Power Loss

Calculate speaker wire gauge needed for cable length, impedance and acceptable loss.

Cable Length (one way)

Length measurement

Speaker Impedance

Electrical impedance in ohms

Max Acceptable Loss

Enter the max acceptable loss

How We Calculate This

Cable Resistance

R = resistance per metre × (cable length × 2)

The cable length is doubled because the signal must travel through both the positive and negative conductors (out and back).

Power Loss

Loss (%) = R_cable / (R_speaker + R_cable) × 100

Loss (dB) = 20 × log10(R_speaker / (R_speaker + R_cable))

The cable and speaker form a voltage divider, so the loss is a voltage ratio (20 × log10) — equivalently 10 × log10 of the power ratio, which gives the same figure. A 5% power loss is about 0.45 dB; a 2% loss about 0.18 dB.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates based on standard formulas. Always verify results for critical applications.