Watts To Amps Calculator: How Many Watts In An Amp?

Example: An air conditioner is powered by 800 Watts. How many Amps is that? It’s 5 Amps.

To convert electrical power to electrical current (Watts to Amps), we need to use the electrical power equation:

P = I*V


  • 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. 

Watts To Amps Calculator (W to A)

Here you can easily convert watts to amps using this calculator:

0.00 Amps

Calculated Amps


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.

At 240V, 240 watts make 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.

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.

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

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.

15 thoughts on “Watts To Amps Calculator: How Many Watts In An Amp?”

  1. 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

    • 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 …

    • 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.

  2. 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

    • 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.

  3. 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 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.


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