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First, the notes: We hope this solar calculator will make sizing your panels and batteries a little less painful. Keep in mind that this is only a calculator, and it will directly reflect whatever you, the user, inputs into the fields. If your base calculations are off by even a little bit, the results reflected can be skewed by quite a bit, so view this as a guide, not an absolute. With that said, here comes the disclaimer. This calculator is for educational purposes only. BatteryStuff.com is in no way responsible for the results of your calculations, and if you purchase a system based on the results of the Solar Calculator, BatteryStuff will not and cannot be held responsible for returns or exchanges for improperly sized systems. Normal RMA and exchange rules will apply to all solar panel purchases. See BatteryStuff.com policies for more info.
Now the instructions:
Field #3: This field needs to be DC watt draw only. If you are using an DC to AC power inverter, meaning your device is rated in AC amps and 110 V, you will need to convert that number into DC watts before entering it in the field. Then you will need to add about 10% due to the inefficiency of the power inverter. To get there, use the following formulas;
1 Amp AC = 10 Amps DC. (example, 2AC amps =20DC amp)
Add 10% (22 amps)
DC amps x 12v = DC watts. (22 x12 =264 watts)
264 would be entered in field # 3
Fields #6 and #12 are for how many hours you expect your equipment to run in a 24 hour period, and your input voltage (12, 24, 36?).
Fields #14 and #18 will determine what size and how many batteries you need. In #14, insert days of backup you would like your battery pack to be good for. This is minus any solar panels, which we will figure in a minute. Field #18 is based on what battery you choose. Say you want to use a 55 AH battery because you like the dimensions, or maybe you like the 21 AH battery due to its terminal configuration. Enter your chosen battery amps there. We don’t like to see any battery discharged more than about 50%, so we will automatically adjust for that.
Still with me? Good, we are almost done. The last two fields, #22 and #25 are easy. How many hours of direct sunlight do you estimate your panel will get. Be realistic. We will then automatically guesstimate for clouds, bad weather etc. Field #25 is just like field #18 in the battery section. Look at our solar page, pick a panel you like and then enter the watts here.
I am ready, take me to the calculator!
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How to convert electric current in amps (A) to electric power in watts (W).
You can calculate watts from amps and volts. You can't convert amps to watts since watts and amps units do not measure the same quantity.
- DC amps to watts
- AC single phase amps to watts
- AC three phase amps to watts
DC amps to watts calculation formula
The power P in watts (W) is equal to the current I in amps (A), times the voltage V in volts (V):
P(W) = I(A) × V(V)
So watts are equal to amps times volts:
watt = amp × volt
or
W = A × V
Example
What is power consumption in watts when the current is 3A and the voltage supply is 110V?
Answer: the power P is equal to current of 3 amps times the voltage of 110 volts.
P = 3A × 110V = 330W
AC single phase amps to watts calculation formula
The real power P in watts (W) is equal to the power factor PF times the phase current I in amps (A), times the RMS voltage V in volts (V):
P(W) = PF × I(A) × V(V)
So watts are equal to power factor times amps times volts:
watt = PF × amp × volt
or
W = PF × A × V
Example
What is power consumption in watts when the power factor is 0.8 and the phase current is 3A and the RMS voltage supply is 110V?
Answer: the power P is equal to power factor of 0.8 times current of 3 amps times voltage of 110 volts.
P = 0.8 × 3A × 110V = 264W
AC three phase amps to watts calculation formula
Watts calculation with line to line voltage
The real power P in watts (W) is equal to square root of 3 times the power factor PF times the phase current I in amps (A), times the line to line RMS voltage VL-L in volts (V):
P(W) = √3 × PF × I(A) × VL-L(V)
So watts are equal to square root of 3 times power factor PF times amps times volts:
watt = √3 × PF × amp × volt
or
W = √3 × PF × A × V
ExampleWhat is power consumption in watts when the power factor is 0.8 and the phase current is 3A and the RMS voltage supply is 110V?
Answer: the power P is equal to power factor of 0.8 times current of 3 amps times the voltage of 110 volts.
P = √3 × 0.8 × 3A × 110V = 457W
Watts calculation with line to neutral voltage
The calculation assumes the loads are balanced.
The real power P in watts (W) is equal to 3 times the power factor PF times the phase current I in amps (A), times the line to neutral RMS voltage VL-0 in volts (V):
P(W) = 3 × PF × I(A) × VL-0(V)
So watts are equal to 3 times power factor PF times amps times volts:
watt = 3 × PF × amp × volt
or
W = 3 × PF × A × V
How to convert watts to amps ►
See also
Volts (V) to amps (A) calculator.
Select calculation type, enter volts and watts or ohms and press the Calculate button to get amps:
Amps to volts calculator ►
Volts to amps calculation
The current I in amps (A) is equal to the power P in watts (W), divided by the voltage V in volts (V):
I(A) = P(W) / V(V)
The current I in amps (A) is equal to the voltage V in volts (V) divided by the resistance R in ohms (Ω):
I(A) = V(V) / R(Ω)
Volts to amps calculation ►
See also
Example: A 120V air conditioner is powered by 900 Watts. How many Amps is that? It’s 7.5 Amps.
How to find amperage or amps from watts?
To convert electrical power to electrical current (Watts to Amps), we need to use the electrical power equation:
P = I × V or Watts = Amps × Volts
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 or 240V. Batteries run at 12V or 24V.
Using this equation, we can convert watts directly to amps, if we know the voltage. The higher the wattage, the lower the amps will be for the same amount of watts.
To help you out, we have prepared an easy-to-use Watts To Amps calculator. Below the calculator, you will find examples of how to make the conversion and 5 calculated tables of watts to amps as 12V, 24V, 120V, 220V, and 240V.
Watts To Amps Calculator (W to A)
Here you can easily convert watts to amps using this calculator. You can play around with numbers a bit as well:
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 systems to see how many amps they run on.
Watts To Amps At 12V (For Batteries)
1 Watt to amps at 12V: | 83 mA (milliamps) |
10 Watts to amps at 12V: | 830 mA |
50 Watts to amps at 12V: | 4.17 Amps |
100 Watts to amps at 12V: | 8.33 Amps |
200 Watts to amps at 12V: | 16.67 Amps |
300 Watts to amps at 12V: | 25.00 Amps |
400 Watts to amps at 12V: | 33.3 Amps |
500 Watts to amps at 12V: | 41.7 Amps |
600 Watts to amps at 12V: | 50.0 Amps |
700 Watts to amps at 12V: | 58.3 Amps |
800 Watts to amps at 12V: | 66.7 Amps |
900 Watts to amps at 12V: | 75.0 Amps |
1000 Watts to amps at 12V: | 83.3 Amps |
1100 Watts to amps at 12V: | 91.7 Amps |
1200 Watts to amps at 12V: | 100.0 Amps |
1300 Watts to amps at 12V: | 108.3 Amps |
1400 Watts to amps at 12V: | 116.7 Amps |
1500 Watts to amps at 12V: | 121.7 Amps |
1800 Watts to amps at 12V: | 150.0 Amps |
2000 Watts to amps at 12V: | 166.7 Amps |
2500 Watts to amps at 12V: | 208.3 Amps |
3000 Watts to amps at 12V: | 250.0 Amps |
One good example where you need to calculate the amps from watts is 12V wire sizing. If you want to pick the correct size wire for the 12V circuit, you have to know the minimum ampacity you need from your wire. You can check how to correctly calculate a 12V wire size here.
Watts To Amps At 24V (For Batteries)
1 Watt to amps at 24V: | 42 mA (milliamps) |
10 Watts to amps at 24V: | 420 mA |
50 Watts to amps at 24V: | 2.08 Amps |
100 Watts to amps at 24V: | 4.17 Amps |
200 Watts to amps at 24V: | 8.33 Amps |
300 Watts to amps at 24V: | 12.50 Amps |
400 Watts to amps at 24V: | 16.67 Amps |
500 Watts to amps at 24V: | 20.83 Amps |
600 Watts to amps at 24V: | 25.00 Amps |
700 Watts to amps at 24V: | 29.17 Amps |
800 Watts to amps at 24V: | 33.33 Amps |
900 Watts to amps at 24V: | 37.50 Amps |
1000 Watts to amps at 24V: | 41.67 Amps |
1100 Watts to amps at 24V: | 45.83 Amps |
1200 Watts to amps at 24V: | 50.00 Amps |
1300 Watts to amps at 24V: | 54.17 Amps |
1400 Watts to amps at 24V: | 58.33 Amps |
1500 Watts to amps at 24V: | 62.50 Amps |
1800 Watts to amps at 24V: | 75.00 Amps |
2000 Watts to amps at 24V: | 83.33 Amps |
2500 Watts to amps at 24V: | 104.17 Amps |
3000 Watts to amps at 24V: | 125.00 Amps |
Watts To Amps At 120V (Standard Outlet)
100 Watts to amps at 120V: | 0.83 Amps |
200 Watts to amps at 120V: | 1.67 Amps |
300 Watts to amps at 120V: | 2.50 Amps |
400 Watts to amps at 120V: | 3.33 Amps |
500 Watts to amps at 120V: | 4.17 Amps |
600 Watts to amps at 120V: | 5.00 Amps |
700 Watts to amps at 120V: | 5.83 Amps |
800 Watts to amps at 120V: | 6.67 Amps |
900 Watts to amps at 120V: | 7.50 Amps |
1000 Watts to amps at 120V: | 8.33 Amps |
1100 Watts to amps at 120V: | 9.17 Amps |
1200 Watts to amps at 120V: | 10.00 Amps |
1300 Watts to amps at 120V: | 10.83 Amps |
1400 Watts to amps at 120V: | 11.67 Amps |
1500 Watts to amps at 120V: | 12.17 Amps |
1800 Watts to amps at 120V: | 15.00 Amps |
2000 Watts to amps at 120V: | 16.67 Amps |
2500 Watts to amps at 120V: | 20.83 Amps |
3000 Watts to amps at 120V: | 25.00 Amps |
Example: How many amps is 1,500 watts at 120V? Simply consult the chart: There are 12.17 amps in 1,500 watts (at 120V voltage).
Watts To Amps At 220V (220V Outlet)
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 |
Example: In many cases, you need to convert watts to amps if you are looking to find an adequate size wire for AC. You can look at examples of how this is done by checking the air conditioner wire size calculator here and the AC breaker size chart here.
Watts To Amps At 240V (240V Outlet)
100 Watts to amps at 240V: | 0.42 Amps |
200 Watts to amps at 240V: | 0.83 Amps |
300 Watts to amps at 240V: | 1.25 Amps |
400 Watts to amps at 240V: | 1.67 Amps |
500 Watts to amps at 240V: | 2.08 Amps |
600 Watts to amps at 240V: | 2.50 Amps |
700 Watts to amps at 240V: | 2.92 Amps |
800 Watts to amps at 240V: | 3.33 Amps |
900 Watts to amps at 240V: | 3.75 Amps |
1000 Watts to amps at 240V: | 4.17 Amps |
1100 Watts to amps at 240V: | 4.58 Amps |
1200 Watts to amps at 240V: | 5.00 Amps |
1300 Watts to amps at 240V: | 5.42 Amps |
1400 Watts to amps at 240V: | 5.83 Amps |
1500 Watts to amps at 240V: | 6.25 Amps |
1800 Watts to amps at 240V: | 7.50 Amps |
2000 Watts to amps at 240V: | 8.33 Amps |
2500 Watts to amps at 240V: | 10.42 Amps |
3000 Watts to amps at 240V: | 12.50 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.
Note: Figuring out watts to amps can help you, for example, to calculate how long does it take to charge a Tesla car.
When you figure out amps, you will probably need adequate wiring for your amp size. You can consult the ampacity AWG chart with wire sizes in mm, mm2, and amps here.
You can also check what wire sizes you need to conduct certain amps: