What Gauge Extension Cord Do You Need for a 200 Ft Run? | 12 vs 10 AWG

For a 200 ft run on 120 volts, 12 AWG is the usual starting point, while 10 AWG is the safer pick for tools, motors, and heavier loads.

A 200-foot cord is not a 200-foot electrical path. Current travels out to the tool and back, so the run behaves like 400 feet of conductor. That doubling is why a cord that spins a drill at 25 feet can stall a mower at 200, and it is the number behind what gauge extension cord you need for a 200 ft run. Two things set the answer: the amps the device pulls, and how much voltage you can afford to lose on the way.

Extension Cord Gauge On A 200 Ft Run: Where The Loss Adds Up

Voltage drop is the price of distance, and at 200 feet it decides whether a setup works or limps. Copper resists current, resistance builds over the full round trip, and the tool only receives what is left at the far end.

Pro Tool Reviews’ extension cord size chart lists the drop for a standard 15-amp, 120-volt load over 200 feet of cord:

Wire tables back this up. Thicker copper costs more and weighs more, and it also loses less — at 200 feet, that trade is the entire decision.

12 AWG Or 10 AWG For 200 Ft?

For light loads, 12 AWG usually works at 200 ft. For tools, motors, or anything with a startup surge, 10 AWG is the better call, and the dividing line is current rather than length alone.

Common design targets aim for about 3% voltage drop on the cord itself and about 5% for the feeder and branch circuit combined. Those come from NEC informational notes rather than a single mandatory rule, so treat them as a practical ceiling.

The 3% and 5% targets exist because equipment is built around nominal voltage. Feed a motor 113 volts instead of 120 and it draws extra current to make up the difference, which means more heat in the windings and a shorter service life.

At a 15-amp draw, a 12 AWG cord loses about 4.9% at 200 feet — workable, but with nothing to spare. Step down to 14 AWG and the loss jumps to about 7.8%, enough to slow a saw, dim the lights on the same circuit, and warm the cord.

Motors, compressors, mowers, and pressure washers pull a startup spike several times their running current, and that first half-second is when a marginal cord trips a breaker or refuses to start the tool. If your device fits that description, buy 10 AWG and skip the debate. For anything else, a voltage drop formula guide lets you check your own numbers in about a minute.

What Else Keeps A Long Cord Safe?

An amp rating stamped on the jacket is a ceiling, not a plan. A 14 AWG cord rated for 15 amps can still brown out a tool at 200 feet, because the label says nothing about how long the run is.

A cord that is too thin for the load can cause brownouts, sluggish tool performance, overheating, and nuisance breaker trips. The damage is rarely dramatic — the tool simply underperforms, and the copper gets warm.

Two habits prevent most of it. Keep the cord fully uncoiled during use when the manufacturer says to, since a tight coil traps heat. And for outdoor or wet locations, use an outdoor-rated cord with listed protection instead of a standard indoor one.

Before you buy, work through this order:

1. Read the device nameplate for amps or watts.
2. Double the distance — 200 ft one way is 400 ft of conductor.
3. Choose the smallest gauge that keeps both ampacity and voltage drop in range.
4. Step one size thicker for motors, compressors, mowers, and pressure washers.

When the numbers line up, the tool runs at full speed and the cord stays cool to the touch. Our tested picks for a 200 ft extension cord roundup list gauge and jacket rating side by side, so you can match a cord to the device you already own.