Speaker Wire Gauge Calculator
What gauge speaker wire do you need?
Calculate the right speaker wire gauge (AWG) from cable length and speaker impedance. See resistance, signal loss in dB, and max run length per gauge.
How it works
The math behind the answer
Speaker wire adds resistance in series with your speaker. Too much resistance wastes amplifier power as heat, lowers the level slightly, and reduces the amplifier's control over the woofer (damping factor). The fix is simple: thicker wire for longer runs and lower-impedance speakers.
The common engineering rule is to keep the round-trip cable resistance at or below 5% of the speaker's nominal impedance. This calculator applies that rule using published copper resistance per gauge, doubling the run length to account for both conductors.
Because 16 AWG costs barely more than 18 AWG, the tool recommends 16 AWG as a practical floor even when thinner wire technically passes. It also shows how far you can run each gauge before exceeding the target.
Common questions
- Is 16 gauge speaker wire good enough?
- For 8 ohm speakers, 16 AWG keeps losses under 5% out to just under 50 feet. For 4 ohm speakers or longer runs, step up to 14 or 12 AWG.
- Does expensive speaker wire sound better?
- No. Gauge, length, and copper purity determine resistance, and resistance is the only thing that matters at audio frequencies over domestic distances. Buy decent pure copper wire and spend the savings elsewhere.
- What is CCA wire?
- Copper-clad aluminum. It is cheaper but has about 60% more resistance than pure copper for the same gauge, so you need to go two gauges thicker to match. Avoid it when you can.