Enter your Current Load (Amps), Wire Length, System Voltage, and Max Voltage Drop (%) into the Automotive Wire Size Calculator, toggle conditions like High Temperature or Continuous Load, and get your Recommended Wire Gauge alongside Actual Voltage Drop and Adjusted Current.
Recommended Wire Gauge
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Actual Voltage Drop
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Adjusted Current
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Wire Capacity
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AWG (American Wire Gauge) is a standardized system for measuring wire diameter. Larger AWG numbers indicate thinner wires. Using the correct wire gauge prevents voltage drop, overheating, and electrical fires in automotive applications.
Using undersized wire can cause excessive voltage drop, leading to poor performance of electrical components, overheating, potential fire hazards, and premature failure of electrical devices.
High temperatures, continuous loads, and wire bundling all reduce a wire's current-carrying capacity. These conditions require using larger gauge wire to maintain safety and performance.
Generally, 3% voltage drop is acceptable for automotive circuits. Critical circuits like ignition may require even less (1-2%), while some accessories can tolerate up to 5%.
Yes, your wire must be rated for at least the fuse amperage. The fuse protects the wire, so using wire rated below the fuse rating creates a safety hazard.
No, automotive applications require wire rated for the operating temperature and vibration conditions found in vehicles. Use automotive-grade wire with appropriate temperature ratings.
Measure the one-way distance from the power source to the load. The calculator accounts for the return path automatically in its voltage drop calculations.
Yes, using larger wire than calculated is always safe and will result in lower voltage drop and better performance. The main considerations are cost and physical space constraints.