Volts to Watts (V to W) Conversion Calculator

To convert volts to watts, the formula is watts = volts x amps. For example, if you have a 12 volt fridge that uses 5 amps, the calculation would be 12 x 5 = 60 watts.

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watts
Conversion formula: watts = volts × amps

Volts to Watts Conversion Charts

Here are some tables converting common AC and DC voltages to watts at various levels of current.

5 Volts to Watts

Volts (V)Amps (A)Watts (W)
5 V1 A5 W
5 V2 A10 W
5 V3 A15 W
5 V4 A20 W
5 V5 A25 W
5 V6 A30 W
5 V7 A35 W
5 V8 A40 W
5 V9 A45 W
5 V10 A50 W

12 Volts to Watts

Volts (V)Amps (A)Watts (W)
12 V1 A12 W
12 V2 A24 W
12 V3 A36 W
12 V4 A48 W
12 V5 A60 W
12 V6 A72 W
12 V7 A84 W
12 V8 A96 W
12 V9 A108 W
12 V10 A120 W

24 Volts to Watts

Volts (V)Amps (A)Watts (W)
24 V1 A24 W
24 V2 A48 W
24 V3 A72 W
24 V4 A96 W
24 V5 A120 W
24 V6 A144 W
24 V7 A168 W
24 V8 A192 W
24 V9 A216 W
24 V10 A240 W

36 Volts to Watts

Volts (V)Amps (A)Watts (W)
36 V1 A36 W
36 V2 A72 W
36 V3 A108 W
36 V4 A144 W
36 V5 A180 W
36 V6 A216 W
36 V7 A252 W
36 V8 A288 W
36 V9 A324 W
36 V10 A360 W

48 Volts to Watts

Volts (V)Amps (A)Watts (W)
48 V1 A36 W
48 V2 A72 W
48 V3 A108 W
48 V4 A144 W
48 V5 A180 W
48 V6 A216 W
48 V7 A252 W
48 V8 A288 W
48 V9 A324 W
48 V10 A360 W

110 Volts to Watts

Volts (V)Amps (A)Watts (W)
110 V1 A110 W
110 V2 A220 W
110 V3 A330 W
110 V4 A440 W
110 V5 A550 W
110 V6 A660 W
110 V7 A770 W
110 V8 A880 W
110 V9 A990 W
110 V10 A1100 W

120 Volts to Watts

Volts (V)Amps (A)Watts (W)
120 V1 A120 W
120 V2 A240 W
120 V3 A360 W
120 V4 A480 W
120 V5 A600 W
120 V6 A720 W
120 V7 A840 W
120 V8 A960 W
120 V9 A1080 W
120 V10 A1200 W

220 Volts to Watts

Volts (V)Amps (A)Watts (W)
220 V1 A220 W
220 V2 A440 W
220 V3 A660 W
220 V4 A880 W
220 V5 A1100 W
220 V6 A1320 W
220 V7 A1540 W
220 V8 A1760 W
220 V9 A1980 W
220 V10 A2200 W

230 Volts to Watts

Volts (V)Amps (A)Watts (W)
230 V1 A230 W
230 V2 A460 W
230 V3 A690 W
230 V4 A920 W
230 V5 A1150 W
230 V6 A1380 W
230 V7 A1610 W
230 V8 A1840 W
230 V9 A2070 W
230 V10 A2300 W

240 Volts to Watts

Volts (V)Amps (A)Watts (W)
240 V1 A240 W
240 V2 A480 W
240 V3 A720 W
240 V4 A960 W
240 V5 A1200 W
240 V6 A1440 W
240 V7 A1680 W
240 V8 A1920 W
240 V9 A2160 W
240 V10 A2400 W

How to Convert Volts to Watts (V to W)

To convert volts to watts, simply multiply the device's voltage (in volts) by its amperage (in amps).

Formula: watts = volts × amps

Abbreviated: W = V × A

Occasionally, you may also see watts abbreviated as P instead of W and amps abbreviated as I instead of A. The conversion formula remains the same.

Alternate abbreviation: P = V × I

Example

Here's a simple example illustrating how to convert volts to watts.

Let's assume you own the following solar panel that is rated at 18.6 volts and 5.38 amps.

To calculate the watts produced by the panel in full sun, you would multiply volts times amps.

18.6 volts × 5.38 amps = 100.07 watts

It turns out your panel is a 100 watt solar panel.

Why Convert Volts to Watts?

Knowing a device's wattage is necessary for estimating how much power it's using at a given moment, as well as how much energy it consumes overall.

For example, let's say you have this portable 12 volt fridge.

You look at its product specifications and see that it has a max current of 5 amps. To estimate its max power consumption in watts, you multiply its voltage by its amperage.

12 V × 5 A = 60 W

So, in this example, your 12 volt fridge uses a max of 60 watts.

It's important to know that the current rating listed on a device is usually its max current rating. In other words, the device may not be always using that much current. Fridges, for instance, enter a cooling cycle when the internal temperature gets too high. During a cooling cycle, a fridge is using much more energy than when it's simply insulating.

Knowing the wattage of your devices helps you do three main things when it comes to DIY solar power:

  1. Size an inverter
  2. Estimate energy usage
  3. Size a battery bank

1. Sizing an Inverter

Inverters are rated in watts. If you know the wattage of all your devices, you can sum them together to get your system's total power draw. This is the total watts being used if all your devices were running at peak power simultaneously.

For instance, let's say you plan to run a 200 watt fridge and a 75 watt fan off your inverter. You'd find your system's max power draw by summing the wattage of these two devices.

200 W + 75 W = 275 W

Your inverter needs to have a watt rating higher than this total. So a 250 watt inverter would be insufficient, but a 500 watt inverter would work.

2. Estimating Energy Usage

Power is rated in watts, but energy is rated in watt hours or kilowatt hours. To estimate energy usage of your house or DIY electrical system, you need to convert watts to watt hours (or watts to kilowatt hours).

To do so, you need to know the wattage of all your devices as well as how many hours per day each one will run on average.

If you have a 75 watt TV that runs for 2 hours each day, for instance, you can estimate its watt hours (Wh) by multiplying watts by hours.

75 W × 2 hrs = 150 Wh

Each day, your TV uses about 150 watt hours of energy.

3. Sizing a Battery Bank

The amount of energy a battery stores can also be expressed in watt hours or kilowatt hours. (Though often it is expressed in amp hours, which must be converted to watt hours or kilowatt hours.) So, if you know your estimated energy usage, you can use that number to size your battery bank.

For example, let's say you're designing a small off-grid solar power system. All together, you expect your devices to consume 200 watt hours per day. You want your battery to last for up to 3 days without recharging, so you could size your battery bank by multiplying the two numbers together to get the total energy usage of your system over the course of 3 days.

200 Wh/day × 3 days = 600 Wh

In this simplified example, your battery bank needs to have a capacity of at least 600 watt hours to meet your energy requirements.

How to Convert Watts to Volts (W to V)

To convert watts to volts, divide watts by amps.

Formula: volts = watts ÷ amps

Abbreviated: V = W ÷ A

Alternate abbreviation: V = P ÷ I

Example

For example, let's say you have a 300 watt solar panel that is also rated at 12.5 amps. You want the panel's voltage. Simply divide watts by amps to get volts.

300 watts ÷ 12.5 amps = 24 volts

Turns out your panel is a 24 volt solar panel.

How to Convert Amps to Watts (A to W)

To convert amps to watts, multiply amps times volts.

Formula: watts = amps × volts

Abbreviated: W = A × V

Alternate abbreviation: P = I × V

Example

Let's say you have a portable travel oven you want to use while on a road trip in your campervan. The oven is rated at 12 volts and 10.8 amps.

You calculate the maximum watts used by the oven by multiplying amps times volts.

10.8 amps × 12 volts  = 129.6 watts
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Alex Beale
Alex Beale is the founder and owner of Footprint Hero. As a self-taught DIY solar enthusiast, Alex has spent 4 years producing educational solar content across YouTube, TikTok, Instagram, and the Footprint Hero blog. During that time, he's built Footprint Hero to over 7 million blog visits and 18 million YouTube views. He lives in Tennessee.