WireGauge: DC Wire Size

WireGauge finds the right copper wire size for low-voltage DC circuits on boats, RVs, campers, vans, solar setups and vehicles - the fast, no-guesswork way.

Most "wire size" charts only check one thing. WireGauge checks BOTH limits that actually matter and tells you which one decides your gauge:

SIZE IT IN SECONDS
- Enter current (amps), one-way run length, and system voltage (12 / 24 / 48 V).
- Get the smallest safe AWG, the real voltage drop in volts and percent, and the wire's ampacity.
- See at a glance whether voltage drop or ampacity is the limiting factor.

TWO CHECKS, ONE ANSWER
- Voltage drop uses the standard ABYC round-trip model (2 x length x resistance x current).
- Ampacity follows ABYC E-11 Table 6A, with insulation temperature rating (60/75/90/105C) and bundle derating.
- Pick 3% for critical circuits (panels, electronics, nav lights) or 10% for non-critical loads - or set your own.

WORK IT BACKWARDS
- Have a spool already? Enter the AWG and find the maximum run length, or the maximum load current it can carry.

QUICK REFERENCE
- Built-in AWG table: cross-section in mm2, ampacity by temperature rating, and resistance per 1000 ft.

MADE FOR THE JOB
- Big, high-contrast readout that works in a garage or on deck.
- Copy any result to share or save.
- Buy once. No subscription. No ads. Works completely offline, with nothing to sign in to and no data leaving your device.

WireGauge is a planning aid based on ABYC E-11 and standard copper resistance. It is not a substitute for the ABYC standard, a licensed electrician, or local code, and does not size overcurrent protection (fuses/breakers). Always verify before wiring.