Practical tools for measured work
Speaker Cable Gauge & Loss Calculator
Compare copper AWG loop resistance and signal loss, then select the thinnest gauge within a chosen limit.
The recommendation is the thinnest listed copper gauge that meets the entered voltage-loss limit. Lower AWG numbers are thicker.
How it works
How to use it: enter one-way run length, nominal speaker impedance, amplifier power and the largest acceptable cable drop.
Formula. Loop resistance is twice length times copper resistance per metre. Voltage loss = cable resistance / (speaker plus cable resistance).
Example. A 12 m one-way run contains 24 m of conductor, so both legs must be included.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- One-way cable length
- 12 m
- Nominal speaker impedance
- 8 ohm
- Maximum voltage loss
- 5 %
- Amplifier power
- 100 W
Primary result: Thinnest listed gauge within limit: 16 AWG.
Before using the result
- Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
- Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
- When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.
Limitations
This assumes copper at about 20 C and a resistive nominal load. Speaker impedance changes with frequency; connectors, copper-clad aluminium, temperature and local electrical rules can require a heavier cable. In-wall cable must have the correct fire rating.
Frequently asked questions
Is 12 AWG always better?
It has lower resistance, but may be unnecessary, harder to terminate and more expensive. Choose a gauge that meets loss and installation requirements.
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