guide · energy

Amps to Watts Chart (1–200 A)

Updated October 29, 2026 · 6 min read

direct answer

Multiply amps by volts. On a standard 120 V outlet, 1 amp = 120 watts, so 15 A = 1,800 W, 20 A = 2,400 W and 30 A = 3,600 W. On a 240 V circuit the same amperages double: 15 A = 3,600 W, 20 A = 4,800 W, 30 A = 7,200 W. On a 12 V battery, 1 amp = 12 watts. The full table for 1–200 A is below — or skip the math with the Amps to Watts Calculator.

Every common conversion in one table, at the three voltages you actually meet: 12 V batteries and solar, 120 V standard outlets, and 240 V large-appliance circuits. All values assume power factor 1.0.

Amps to watts chart: 1–200 A

Watts = amps × volts, precomputed. Find your amperage in the first column and read across for the circuit voltage you have:

Current	12 V (battery, solar)	120 V (standard outlet)	240 V (large appliances)
1 A	12 W	120 W	240 W
2 A	24 W	240 W	480 W
3 A	36 W	360 W	720 W
4 A	48 W	480 W	960 W
5 A	60 W	600 W	1,200 W
6 A	72 W	720 W	1,440 W
7 A	84 W	840 W	1,680 W
8 A	96 W	960 W	1,920 W
9 A	108 W	1,080 W	2,160 W
10 A	120 W	1,200 W	2,400 W
11 A	132 W	1,320 W	2,640 W
12 A	144 W	1,440 W	2,880 W
13 A	156 W	1,560 W	3,120 W
14 A	168 W	1,680 W	3,360 W
15 A	180 W	1,800 W	3,600 W
16 A	192 W	1,920 W	3,840 W
17 A	204 W	2,040 W	4,080 W
18 A	216 W	2,160 W	4,320 W
19 A	228 W	2,280 W	4,560 W
20 A	240 W	2,400 W	4,800 W
21 A	252 W	2,520 W	5,040 W
22 A	264 W	2,640 W	5,280 W
23 A	276 W	2,760 W	5,520 W
24 A	288 W	2,880 W	5,760 W
25 A	300 W	3,000 W	6,000 W
26 A	312 W	3,120 W	6,240 W
27 A	324 W	3,240 W	6,480 W
28 A	336 W	3,360 W	6,720 W
29 A	348 W	3,480 W	6,960 W
30 A	360 W	3,600 W	7,200 W
35 A	420 W	4,200 W	8,400 W
40 A	480 W	4,800 W	9,600 W
45 A	540 W	5,400 W	10,800 W
50 A	600 W	6,000 W	12,000 W
60 A	720 W	7,200 W	14,400 W
70 A	840 W	8,400 W	16,800 W
80 A	960 W	9,600 W	19,200 W
90 A	1,080 W	10,800 W	21,600 W
100 A	1,200 W	12,000 W	24,000 W
125 A	1,500 W	15,000 W	30,000 W
150 A	1,800 W	18,000 W	36,000 W
175 A	2,100 W	21,000 W	42,000 W
200 A	2,400 W	24,000 W	48,000 W

The formula behind every row

Each cell is one multiplication: W = A × V. Anything not on the chart takes five seconds: 37 A on a 240 V welder circuit is 37 × 240 = 8,880 W. The reverse — watts to amps — is just as short: A = W ÷ V. A 1,500 W space heater on 120 V draws 12.5 A; the same heater on 230 V mains draws 6.5 A. For AC circuits with motors or electronics, multiply by the power factor (typically 0.8–0.95): a 10 A, 120 V compressor at PF 0.8 delivers 960 W of real work, not the 1,200 W the chart shows. The calculator handles the PF and three-phase math for you.

Worked examples from the chart

Space heater on a 15 A outlet: the chart gives 1,800 W at 120 V — a 1,500 W heater fits with room to spare, and two of them (3,000 W) will trip the breaker.
Dryer on a 30 A, 240 V circuit: 7,200 W available, so a 5,600 W dryer is well within limits even after the 80% continuous-load rule.
100 W load on a 12 V battery: the chart read in reverse — 100 ÷ 12 ≈ 8.3 A — explains why a car battery running an inverter drains fast: every 120 W of AC output pulls 10 A from the battery.
Inverter sizing: a 20 A, 120 V well pump needs 2,400 W of chart power, but the motor's starting surge can triple that — which is where a wattage sizing calculator earns its keep.

Three-phase values (quick correction)

The chart covers single-phase and DC circuits. For three-phase power — commercial panels, large pumps, workshop machinery — multiply the 240 V column value by 1.732 × PF. At PF 0.9, a 20 A three-phase circuit delivers 20 × 240 × 1.732 × 0.9 ≈ 7,482 W, versus 4,800 W single-phase. The calculator has a three-phase mode that applies the factor for you.

skip the table

Amps to Watts Calculator

Any amps, any volts, DC or three-phase, with an adjustable power factor. It also shows the NEC 80% continuous limit for the circuit you're checking.

Convert a value

Keep reading

New to the three units? Start with amps vs watts vs volts — the water analogy and the one formula behind the whole chart. Checking a real circuit before plugging in? The circuit capacity guide applies the NEC 80% rule breaker by breaker.

faq

Frequently Asked Questions

Four quick reads on the chart's most-looked-up values.

How do I convert 15 amps to watts?

Multiply amps by volts. 15 A on a standard 120 V outlet is 15 × 120 = 1,800 W; on a 240 V circuit it is 3,600 W; on a 12 V battery it is 180 W. The same amperage means different watts at different voltages, which is why the voltage column matters as much as the amp value.

How many watts is 30 amps at 240 volts?

7,200 W, from 30 × 240. That is the theoretical maximum; under the NEC 80% continuous-load rule a 30 A circuit should carry no more than 5,760 W for loads running three hours or more — which is why electric dryers are designed to draw well under the breaker rating.

Does power factor change the values in the chart?

Yes, for anything with a motor, compressor or electronic power supply. The chart assumes power factor 1.0 (exact for heaters, bulbs and batteries). At PF 0.8, real watts are 20% lower than the chart value: a 10 A, 120 V compressor is listed at 1,200 W but actually delivers about 960 W of work. Divide the chart number by the power factor to get volt-amps, which is what generators and inverters are sized on.

How many watts is 100 amps?

It depends on the voltage: 1,200 W on a 12 V battery bank, 12,000 W on a 120 V service, and 24,000 W on 240 V. A 100 A, 240 V residential service entrance therefore supports a theoretical 24,000 W across all circuits combined, before the 80% continuous-load rule brings the safe continuous figure to 19,200 W.