Enter current, run length, and material to find the voltage drop, diameter, and cross-sectional area for 2 AWG wire.
How to Use the #2 Gauge Wire Calculator
Enter the load current, the one-way distance from source to load in feet, and pick copper or aluminum with the toggle. The system voltage field defaults to 120 V — change it if you're wiring at 240 V or something else entirely.
Most wire-size calculators make you pick a gauge from a list first. This one skips that step because 2 AWG shows up often enough on its own — it's a workhorse size for main service entrance conductors in smaller residential panels, subpanel feeders, and 220-240V welder circuits, common enough to deserve a page that assumes the gauge rather than asking for it.
Why Voltage Drop Matters at This Gauge
2 AWG copper has a fixed diameter of 6.544 mm and a cross-sectional area of 33.6 mm² — geometric facts of the AWG standard, not anything that varies by manufacturer. What does vary is how much voltage the wire loses over distance, which depends on resistance per foot, the length of the run, and the current flowing through it.
Voltage Drop = 2 × Length (ft) × Resistance per foot × Current
% Voltage Drop = Voltage Drop ÷ System Voltage × 100The 2× isn't a fudge factor — current has to travel out to the load and back to the source, so a 50-foot run means 100 feet of actual wire carrying current. Skip that and you'll underestimate the drop by half.
Aluminum's resistance per foot runs noticeably higher than copper's at this gauge — roughly 64% higher, mirroring aluminum's higher resistivity — so the same run in aluminum shows a bigger voltage drop and a bigger percentage than copper, even with identical current and length.
There's no code requirement forcing voltage drop under any specific number for most branch circuits, but the National Electrical Code's informal recommendation of staying under 3% gets cited constantly for good reason: past that point, motors run hotter, lights dim measurably, and equipment rated for a specific voltage starts operating outside its comfort zone. This calculator flags a run once it crosses that line.
The resistance figures behind this calculator approximate NEC Chapter 9 Table 8's uncoated-copper values at 75°C — worth checking against the current table before treating a result as final for a real installation, since actual conductor temperature and installation method shift the real-world number somewhat.