Use our interactive calculator to easily convert watts to amps (W to A).
Or would you rather convert amps to watts?
Watts to Amps Conversion Chart
Here's a chart converting watts to amps at common DC voltages.
| Watts | Amps @ 12V | Amps @ 24V | Amps @ 48V |
|---|---|---|---|
| 10 W | 0.83 A | 0.42 A | 0.21 A |
| 20 W | 1.67 A | 0.83 A | 0.42 A |
| 30 W | 2.5 A | 1.25 A | 0.63 A |
| 40 W | 3.33 A | 1.67 A | 0.83 A |
| 50 W | 4.17 A | 2.08 A | 1.04 A |
| 60 W | 5 A | 2.5 A | 1.25 A |
| 70 W | 5.83 A | 2.92 A | 1.46 A |
| 80 W | 6.67 A | 3.33 A | 1.67 A |
| 90 W | 7.5 A | 3.75 A | 1.88 A |
| 100 W | 8.33 A | 4.17 A | 2.08 A |
| 200 W | 16.67 A | 8.33 A | 4.17 A |
| 300 W | 25 A | 12.5 A | 6.25 A |
| 400 W | 33.33 A | 16.67 A | 8.33 A |
| 500 W | 41.67 A | 20.83 A | 10.42 A |
| 600 W | 50 A | 25 A | 12.5 A |
| 700 W | 58.33 A | 29.17 A | 14.58 A |
| 800 W | 66.67 A | 33.33 A | 16.67 A |
| 900 W | 75 A | 37.5 A | 18.75 A |
| 1000 W | 83.33 A | 41.67 A | 20.83 A |
And if you're using alternating current, here's another chart converting watts to amps for common AC voltages.
| Watts | Amps @ 120V | Amps @ 220V | Amps @ 240V |
|---|---|---|---|
| 100 W | 0.83 A | 0.45 A | 0.42 A |
| 200 W | 1.67 A | 0.91 A | 0.83 A |
| 300 W | 2.5 A | 1.36 A | 1.25 A |
| 400 W | 3.33 A | 1.82 A | 1.67 A |
| 500 W | 4.17 A | 2.27 A | 2.08 A |
| 600 W | 5 A | 2.73 A | 2.5 A |
| 700 W | 5.83 A | 3.18 A | 2.92 A |
| 800 W | 6.67 A | 3.64 A | 3.33 A |
| 900 W | 7.5 A | 4.09 A | 3.75 A |
| 1000 W | 8.33 A | 4.55 A | 4.17 A |
| 2000 W | 16.67 A | 9.1 A | 8.33 A |
| 3000 W | 25 A | 13.64 A | 12.5 A |
| 4000 W | 33.33 A | 18.18 A | 16.67 A |
| 5000 W | 41.67 A | 22.73 A | 20.83 A |
How to Convert Watts to Amps (W to A)
The formula to convert watts to amps is simple, and it's the same whether you're working with alternating current (AC) or direct current (DC).
With direct current, electrons only flow in one direction. This is the type of electricity produced by solar panels and stored in batteries. Any device that relies on a battery to operate, such as your laptop or smartphone, uses DC power.
By contrast, alternating current is what you find in the outlets of your home and is what most appliances run on. AC power is necessary for our modern electrical grid, as this type of electrical current is easily transmitted over long distances without much loss in power.
So when considering solar power for your home, for example, the solar panels (and battery, if you have one) will generate and store electricity as direct current. This then needs to be converted to alternating current to power your home, which is done using an inverter.
To convert watts to amps, divide watts by volts.
Formula: amps = watts ÷ volts
Abbreviated: A = W ÷ V
Note that sometimes you'll see current (in this case, amps) abbreviated as I instead of A, and power (in this case, watts) abbreviated as P instead of W. When that's the case, the formula to convert watts to amps is still the same — only the abbreviated version changes.
Alternate abbreviation: I = P ÷ V
This is a variation on what is sometimes called the electrical power formula, P = V × I, which states that power is equal to voltage times current.
Watts (W) are a common unit of power and amps (A) are a common unit of electrical current, so that's why you'll sometimes also see the power formula written as W = V × A.
Example: DC Voltage
Let's look at a common scenario where you may want to convert watts to amps. For example, let's say you want to know the maximum current (expressed in amps) produced by a typical residential solar panel rated at 175 watts.
Next, you'll need to know the voltage. The voltage at maximum power is listed as 'Vmp' in the manufacturer's specifications for your panel. In this example, let's assume your solar panel has a Vmp of 19V.
Calculate amps by dividing watts by volts.
175 watts ÷ 19 volts = 9.21 amps
So the current produced by your solar panel at full power is 9.21 amps.
Example: AC Voltage
In this example, let's assume you want to know the current produced by your new clothes dryer. The appliance itself is rated at 5,600 watts, and plugs into a 240 volt outlet.
Divide watts by volts to calculate amps.
5,600 watts ÷ 240 volts = 23.33 amps
Why Convert Watts to Amps?
Converting watts to amps is important for any kind of solar-powered system, especially a system that powers your home. You want to know the maximum current to make sure that the existing wiring in your home can support your system operating safely.
While rare, fires caused by solar panels can happen when there is more current than the system can handle, resulting in either an electric arc or an excessive build-up of heat.
Another common example we all run into at some point is overloading an outlet. Most residential outlets in the United States can handle a maximum of 16-20 amps, with some older homes only able to accommodate 12 amps.
Let's say you have two window air conditioning units that you want to run at the same time.
These units are rated at 900 watts and 120 volts each. Next, let's calculate the amps by dividing watts by volts.
900 watts ÷ 120 volts = 7.5 amps
If you try to plug both into the same outlet you'll need double the current, or 15 amps. If your outlet is only rated for a maximum of 12 amps, you'll overload the circuit and trip the circuit breaker (or potentially start an electrical fire, if you don't have a circuit breaker for whatever reason!).
How to Convert Amps to Watts (A to W)
To convert amps to watts, multiply amps by volts.
Formula: watts = amps × volts
Abbreviated: W = A × V
Alternate abbreviation: P = I × V
Example: DC Voltage
Let's say you have a portable solar panel you use when camping. You know the panel is rated for 12 volts and 5 amps.
You can calculate the total wattage of the panel by multiplying amps times volts.
5 amps × 12 volts = 60 watts
Turns out you've got a 60 watt solar panel.
Example: AC Voltage
Occasionally, household appliances or devices may not list the watts rating. In this case, look for the input voltage and the amps the appliance draws.
For example, let's say you have a mini fridge that uses 1.5 amps at 240 volts. To calculate watts, simply multiply amps times volts.
1.5 amps × 240 volts = 360 watts
How to Convert Watts to Volts (W to V)
You may also want to convert watts to volts. The formula for this is also easy. Just divide watts by amps.
Formula: volts = watts ÷ amps
Abbreviated: V = W ÷ A
Alternate abbreviation: V = P ÷ I
Example: DC Voltage
In this example, let's say you have a 300 watt solar panel that draws 12.5 amps. To calculate the voltage, simply divide watts by amps.
300 watts ÷ 12.5 amps = 24 volts
Example: AC Voltage
For an AC power example, let's assume that you want to calculate the voltage of a freezer for your garage. The freezer is rated at 600 watts and 5 amps.
Divide watts by amps to calculate voltage.
600 watts ÷ 5 amps = 120 volts
