Example: An air conditioner is powered by 900 Watts. How many Amps is that? It’s 7.5 Amps.
To convert electrical power to electrical current (Watts to Amps), we need to use the electrical power equation:
P = I*V
where:
- P is electrical power, measured in Watts (W)
- I is electrical current or amperage, measured in Amps (A).
- V is electrical potential or voltage, measured in Volts (V). The standard voltage for most electrical devices is 110-120V, and upgraded voltage powerful electric devices use 220V.
Using this equation, we can convert watts directly to amps, if we know the voltage.
Table of Contents
Watts To Amps Calculator (W to A)
Here you can easily convert watts to amps using this calculator:
To demonstrate how watts can be converted to amps, we solved a few examples of how many amps is 500 watts, 1000 watts, and 3000 watts. In the end, you will also find a watts-to-amps table at 120V electric potential.
Here’s a quick useful piece of info:
How many watts make an amp?
At 120V, 120 watts make 1 amp. That means that 1 amp = 120 watts.
How many watts in 1 amp at 220 volts?
At 220V, you get 220W per 1 amp.
With that in mind, let’s look at the 3 examples:
Example 1: How Many Amps Is 500 Watts?
Let’s say we have a 500W air conditioner plug into 120 V voltage.
Here is how we can calculate how many amps is 500W:
I = P/V
If we input the P = 500 Watts and V = 120 Volts, we get:
I = 500 Watts/120 Volt = 4.17 Amps
In short, 500 Watts equals 4.17 Amps.
What if the voltage would be 220V?
Let’s calculate how many amps is 500W at 220V:
I = 500 Watts/220 Volt = 2.27 Amps
At 220V, 500W draws 2.27 amps.
Example 2: How Many Amps Is 1000 Watts?
If we repeat the exercise and ask ourselves how many Amps equals 1000 Watts, we get:
I = 1000 Watts/120 Volt = 8.33 Amps
We see that a 1000 W device draws twice as many Amps as a 500 W device.
For 220V, we get this watts to amps calculation:
I = 1000 Watts/220 Volt = 4.55 Amps
In short, 1000W draws 8.33 amps at 120V, and 4.55 amps at 220V.
Example 3: 3000 Watts Equals How Many Amps?
3000 Watt devices can be plugin in 120V or into 220V. In cases with higher wattage, it’s not unusual to use a higher 220 voltage. This is designed to reduce the amperage.
For example, 3000 Watt equals to:
- 25 Amps, if you use 120 V.
- 13.64 Amps, if you use 220 V.
For 25 Amps, for example, you would already need an amp breaker. But if you plug such a device into 220 V, the current generated is only 13.64 Amps (there is no need for amp breakers).
Example: Bigger multi-zone mini-split units usually need amp breakers. You can check 2-zone, 3-zone, 4-zone, and 5-zone mini-split system to see how many amps they run on.
Watts To Amps Table (At 120V)
| Watts: | Amps (at 120V): |
|---|---|
| 100 Watts to amps | 0.83 Amps |
| 200 Watts to amps | 1.67 Amps |
| 300 Watts to amps | 2.50 Amps |
| 400 Watts to amps | 3.33 Amps |
| 500 Watts to amps | 4.17 Amps |
| 600 Watts to amps | 5.00 Amps |
| 700 Watts to amps | 5.83 Amps |
| 800 Watts to amps | 6.67 Amps |
| 900 Watts to amps | 7.50 Amps |
| 1000 Watts to amps | 8.33 Amps |
| 1100 Watts to amps | 9.17 Amps |
| 1200 Watts to amps | 10.00 Amps |
| 1300 Watts to amps | 10.83 Amps |
| 1400 Watts to amps | 11.67 Amps |
| 1500 Watts to amps | 12.17 Amps |
| 1800 Watts to amps | 15.00 Amps |
| 2000 Watts to amps | 16.67 Amps |
| 2500 Watts to amps | 20.83 Amps |
| 3000 Watts to amps | 25.00 Amps |
Watts To Amps Table (At 220V)
| Watts: | Amps (at 220V): |
|---|---|
| 100 Watts to amps at 220 volts: | 0.45 Amps |
| 200 Watts to amps at 220 volts: | 0.91 Amps |
| 300 Watts to amps at 220 volts: | 1.36 Amps |
| 400 Watts to amps at 220 volts: | 1.82 Amps |
| 500 Watts to amps at 220 volts: | 2.27 Amps |
| 600 Watts to amps at 220 volts: | 2.73 Amps |
| 700 Watts to amps at 220 volts: | 3.18 Amps |
| 800 Watts to amps at 220 volts: | 3.64 Amps |
| 900 Watts to amps at 220 volts: | 4.09 Amps |
| 1000 Watts to amps at 220 volts: | 4.55 Amps |
| 1100 Watts to amps at 220 volts: | 5.00 Amps |
| 1200 Watts to amps at 220 volts: | 5.45 Amps |
| 1300 Watts to amps at 220 volts: | 5.91 Amps |
| 1400 Watts to amps at 220 volts: | 6.36 Amps |
| 1500 Watts to amps at 220 volts: | 6.82 Amps |
| 1800 Watts to amps at 220 volts: | 8.18 Amps |
| 2000 Watts to amps at 220 volts: | 9.09 Amps |
| 2500 Watts to amps at 220 volts: | 11.36 Amps |
| 3000 Watts to amps at 220 volts: | 13.64 Amps |
If you have a specific question about how to convert Watts to Amps, you can use the comment section below, and we’ll try to help you out.
Very easy to understand, well done. Thanks
I have a product that plugs into a 120v outlet that draws up to 3000w. Is that safe, or should I consider rewiring the product for 240v? (It’s 120/240 compatible
Hello Damien, if it draws 3000W, the wiring should handle 25 amps. That’s quite a lot. Example: Even the highest BTU 120V air conditionerscan handle about 15 amps. You should use an amp breaker or rewire it to 240V, yes.
It is illegal to make a device that pulls anything over 15 A on 120v because most receptacles can only handle 15 A At 120v and most breakers On receptacles is a 15 A . You can only pull close to 1500w witch is 75% of the breakers capability as if you pull 1800W your at 100% of the breakers capacity and it will trip …
how about duration of time? If 250 watt heater is constantly running for 12 hours lets say how many total amps will that draw?
Hello there, the amperage remains constant. 250-watt heater on 220V will draw a bit more than 1 A. 1 amp is, by definition, 1 C (Coulomb) per second. In short, a 250-watt heater draws about 1 A, if you run it 1h, 6h, 12h, 24h, and so on.
Watts divided by volts =amp
2300 w ÷120 v=19.16 amp
Amp multiply by volt =watts
19.16×120 =2299.999
2300w ÷220v =10.45 amp
10. 45 amp×220 v=2299.99w
Wanting to install a wind turbine 400watts at 12volts output how many amps at 120 vo.ts?
Hello Charlie, 400W at 12V you have 33.3 amps. That’s 3.33 amps if you have 120V.
I have a 240/40 amp a/c and a refrigerator is a 10,000 watt generator sufficient
Hello Louis, 240V * 40 A = 9,600 watts. Be careful about the start wattage; that could be higher than 10,000 W. Otherwise, 10,000 W would be enough, yes.
Question, I am buying a plasma cutter one plugs into 120 outlet and the other into a 220 outlet.other wise they are the same, they both draw 45 amps no more no less. Would the output be the same or would the 45 amps in the 220 be more. Thanks ruben
Hello Ruben, with the input, we can calculate the total wattage. 120V * 45A = 5,400W; and 220V * 45A = 9,900W. So, the input of the 220V unit is almost twice as high as the 120V unit. How does that affect the output? Depends upon efficiency, but usually, if you have a 9,900W unit is has a higher output than a 5,400W unit.
Hello, I have a question. Is there a way to determine how many watts a 20 amp AC uses per hour?
Hello Zo, there is a way, yes. You can use the electrical power equation: P (watts ) = I (amps) * V (volts). You already know you have 20 amps. Just include the voltage; either 120V or 220V. Let’s say that you have 220V; that would yield P = 20 amps * 220 volts = 4.400 watts. Per hour, that’s 4,4 kWh. Hope this helps.
On a site I am a member of we have a lot of people putting in multiple amplifiers into boats. Often these amps are 15 feet away from the battery so the questions always come up….what size wire do I need to run? This is 12V DC.
So if I install 3 amps rated at 1000 watts each, 15-20 feet from a battery, what size cable should I run to them?
Hello Julian, an interesting question. 1000W amplified on 12V DC will produce 1000W/12V = 83.3A. So, you would need wires that can handle up to about 100 amperes of current. For 100A, you would need #4 AWG copper wires or #2 AWG aluminum conductors; both of them have a minimum conduit size of 1 ¼ inch. Hope this helps.
I am trying to power a 760 watt 2 channel audio amplifier 12 v 125 rms per channel. How many amps would I need the converter to put out?
Hello Chris, for 760 W and 12 V you can use the P = I * V equation. Basically, 760 W / 12 V = 63.3 A. You would need your converter to put out 65 amps minimum.
I have 4 ea. 120 volt heaters that are rated @ 1500 watts each and they are 20 ft from my breaker panel what size wire should I use.
Hello Jim, that’s an interesting question. Each of these units draws a bit less than 15 amps. For 15 amps, you can use 14-gauge wires. Hope you find this useful.
Greetings
I have an electrical panel with 150 Amps
So that means I need 16500 Watts??
Trying to move to a solar panel
I calculate 7 solar panels for a 200 Amp service with four 300 amp/hour batteries
Need your advice
Hello Willy. 150 Amps is a huge current; at 110V, that is 16,500 Watts, yes. Be aware that solar panels produce electricity at a lower voltage (12V or 24V). To get 16,500 Watts at 24V, you would need 687.5 Amps. Hope this helps.
I want to purchase a heat press that has a 220v plug. It uses 6500 watts. Would a 30amp breaker be enough?
Hello Darica, 6500 watts at 220V is a little below 30 amps. 30 amp breaker would be enough in theory. In practice, however, it’s better to get 2 30 amp breakers because the amps are uncomfortably high for only 1 30 amp breaker.
Hi, if I have a load of 182Kw, 220V, how many amps would be sufficient?
Hello Chris, 182 kW is a huge wattage. You can use the electric power equation to easily see how many amps would be sufficient. Here’s the calculation:
182,000W / 220V = 827.3 amps
You’ll need 827.3 amps; that’s quite an enormous amount.
Hi … trying to learn about all this because my kitchen (actually my whole house) is electrically challenged. My fridge is 11.6 Amps & big toaster oven pulls 15 Amps (1800W); they are on the same 20 Amp circuit. I would think this would be too much to run both at the same time, but they have never thrown the circuit. Am I doing the math right? Together I’m coming up with 3192W (26.6 Amps) … shouldn’t that be too much for a 20Amp circuit? Thanks
Hello Sandra, do both run on 120V? If they run on 220-240V, the amps are halved. Additionally, the fridge might draw 11.6 amps when running at 100%. Most fridges run on much a lower percentage and hence draw much fewer amps. If your 10 amp circuit can handle that, you’re fine.
Hello,
I have an inverter AC (1750 watts, 220v). With the equation you provided, it consumes 7.95amps. I am planning to run two of these units through a 5kVA 24Volt Victron inverter/charger with two 200Ah lithium batteries. Is this a feasible setup? Am I correct in saying I can run the AC even 24hrs? Thanks
Hello Franz, two 200 Ah batteries have a 400 Ah capacity. However, the batteries run on 24V while AC runs on 220V. At 220V, it does consume 7.95 amps, your calculation is correct. However, at 24V, it consumes 1750W/24V = 73 amps. That’s about 10x as many amps due to roughly 10x lower voltage. So, if you have 400Ah capacity, that will be enough for 400 Ah / 73 amps = 5.5 hours. You can prolong that time if you don’t run the AC on 100% output but not to 24h. Hope this helps.
We live in our 5th wheel. My wife needs a CPAP with O2 at night. The CPAP transformer uses 140 watts and the O2 concentrator 240 watts, both 120 volt. I’m trying to figure a way to provide power for her needs at night. Generators run out of gas. I was thinking about deep cycle rv batteries and solar panels to charge the batteries during the day. There are many 12v deep cycle batteries that put out 105 AH for their 20 hour capacity. I just don’t know how many batteries or solar panels I will need to facilitate my wife’s needs. She only uses her CPAP and O2 in bed at night. Thanks.
Hello Jim, that’s a difficult case. To simplify it: You would require 140W + 240W = 380W for lets say 12 hours. Can 12V batteries provide that amount of power? To produce 380W, you would need 380W/12V = 32 amps output. If a battery you have in mind can output 105 amps at 12V for 20 hours, that’s a viable option. We simply don’t have the full knowledge to help you out adequately with this one, sorry.
I am considering hard wiring ( with switch boxes) a 250 amp welding mach./ generator to my house. Generator is rated at 10500 watts peak / 9500 watts continuous, is this going to be sufficient to supply power to my 200 amp service
Hello Roy, it depends on the voltage. If you use a 120V generator, you will get 10,500W/120V = 87.5 amps. If you use a 240V generator, you will get 10,500W/240V = 43.75 amps. In both cases, the generator is too weak; it doesn’t provide 200 amps. You would need a much stronger generator for 200 amps.
Hello,
I have a wall baseboards heaters in my basement for a total of 4000Watts. My breaker is 25 Amps. Can I add another 1000 Watts?
Thanks,
Hello Serge, the voltage is 220V? If so, the current baseboard heaters draw 4000W/220V = 18.2 amps. Additional 1000W would add the total to 5000W and 22.7 amps. You can add another 1000W; the net amps draw won’t surpass 25 amps.