12 vs 14
When 12 AWG beats 14 AWG
14 AWG is lighter and cheaper. 12 AWG keeps more voltage at the tool. The useful question is the run length and whether the load is a motor.
Both gauges show up in the 15 A bin at the hardware store. The hang tags look the same. The copper does not. On a 15 A, 120 V load, 14 AWG is already at about 4.6 V (3.8%) at 50 feet and 9.2 V (7.7%) at 100 feet. 12 AWG on the same load is 2.9 V (2.4%) and 5.8 V (4.8%). That is why a circular saw that “ran fine on a short 14” starts to bog on the far side of the driveway.
The actual difference
12 AWG copper is thicker. Resistance from NEC Chapter 9, Table 8 is 1.93 Ω per 1,000 ft versus 3.07 Ω for 14 AWG (uncoated, 75 °C). Same amps, same feet, the 12 AWG path drops about two-thirds the voltage of the 14 AWG path. You pay for that in weight and sticker price. You do not pay for a magic “heavy duty” coating.
| 15 A load | 14 AWG | 12 AWG |
|---|---|---|
| 25 ft | 2.3 V (1.9%) | 1.4 V (1.2%) |
| 50 ft | 4.6 V (3.8%) | 2.9 V (2.4%) |
| 100 ft | 9.2 V (7.7%) | 5.8 V (4.8%) |
Full rows for 10 A and 13 A live on the master chart.
When 14 AWG is enough
- The tool nameplate is well under 15 A (drills, lights, chargers, a small sander).
- The run is short — 25 feet, maybe a tight 50 if the load is modest and not a hard-starting motor.
- The cord and plug are marked for the amps you will actually draw.
- You will not “just add another 50 later.” Length is the reason people outgrow 14 AWG.
When 12 AWG is the right buy
- A 15 A circular saw, miter saw, or similar motor — see the saw guide.
- Fifty feet or more on a 13–15 A load.
- A hundred-foot job. At 100 feet, 12 AWG on 15 A is already near 5%; 10 AWG is the comfortable pick. Read 100-foot gauge.
- You want one cord that can also feed a 15 A table saw without being the weak link.
50 ft 12 AWG SJTW is the usual shop buy.
Weight, coil, and heat
12 AWG is heavier. That matters if you carry it up a ladder every day. It does not matter if the alternative is a saw that runs hot because the voltage at the handle is low. Leaving a thin cord tightly coiled under load is a heat problem on either gauge; unspool what you are using.
Do not use 16 AWG as the tie-breaker
16 AWG is the light-duty aisle. It is not a cheaper 14. If the choice is truly 12 vs 14, stay in that pair. 16 AWG on a 15 A saw is how people learn about tripping breakers and melted jackets.
12 AWG cords for this comparison
Named SJTW cords checked against the Amazon listing for gauge, length, and a live buy box. Links go to Amazon (Associates tag laqaer-20). We may earn a commission. No scores and no prices.
- View on Amazon
Southwire 12/3 SJTW 50 ft outdoor
12 AWG · 50 ft · SJTW outdoor, lighted end, marked 15 A
- View on Amazon
Southwire 12/3 SJTW 100 ft outdoor
12 AWG · 100 ft · SJTW outdoor, lighted end, marked 15 A
This is a 12 AWG cord. At 100 ft and 15 A the copper estimate is about 5.8 V (4.8%). The chart pick for that run is 10 AWG, which we are not linking until a checked in-stock listing exists.