Current strength-to-power converter

formula for converting current to power

Power in an electric circuit is the energy consumed by the load from a source per unit time, indicating its consumption rate. Unit of measurement is watts [W]. Current strength indicates the amount of energy transmitted for the amount of time, that is, it indicates the velocity of transmission. It is measured in amperes [A or Am]. Current flow voltage (potential difference between two points) is measured in volts. Current strength is directly proportional to voltage.

To calculate the ratio of Amp / Watt or W / A, it is necessary to use the well-known Ohm's law. The power is numerically equal to the product of the current flowing through the load and the voltage applied to it. It is determined by one of three equations: P = I * U = R * I² = U² / R.

Therefore, to determine the power of the energy consumption source, when the current strength in the network is known, it is necessary to use the formula: W (watts) = A (amperes) x I (volts). In order to perform reverse conversion, it is necessary to change the power in watts to the power of current consumption in amperes: Watts / Volt. In case of a 3-phase network, one need to take into account the coefficient 1.73 for the current strength in each phase.

How many watts in 1 Ampere and Amperes in 1 Watt?

Calculate how many watts in 1 ampere

To convert watts to amperes at alternating or direct voltage, the following formula is needed:

I = P / U, where

I – current strength in amperes; P – power in watts; U – voltage in volts if the network is three-phase, then I = P/(√3xU), since it is necessary to calculate the voltage in each phase.

The root of three is approximately 1.73.

That is, one watt has 4,5 mAm (1А = 1000mAm) at voltage of 220 volts and 0,083 Am at 12 volts. When it is necessary to convert current into power (to find out how many watts are in 1 ampere), the following formula is applied:

P = I * U or P = √3 * I * U in case of 3-phase network of 380 V.

So, if we deal with a car network of 12 volts, then 1 ampere is 12 watts, and a 220-V household power supply network has the current strength of 220 watts (0.22 kW). Industrial equipment, powered by 380 volts, has 657 watts.

Ampere-Watt Conversion Table

5 Watt0,830,420,210,020,008Ampere
6 Watt1,000,50,250,030,009Ampere
7 Watt1,170,580,290,030,01Ampere
8 Watt1,330,670,330,040,01Ampere
9 Watt1,50,750,380,040,01Ampere
10 Watt1,670,830,420,050,015Ampere
20 Watt3,331,670,830,090,03Ampere
30 Watt5,002,51,250,140,045Ampere
40 Watt6,673,331,670,130,06Ampere
50 Watt8,334,172,030,230,076Ampere
60 Watt10,005,002,500,270,09Ampere
70 Watt11,675,832,920,320,1Ampere
80 Watt13,336,673,330,360,12Ampere
90 Watt15,007,503,750,410,14Ampere
100 Watt16,673,334,170,450,15Ampere
200 Watt33,3316,678,330,910,3Ampere
300 Watt50,0025,0012,501,360,46Ampere
400 Watt66,6733,3316,71,820,6Ampere
500 Watt 83,3341,6720,832,270,76Ampere
600 Watt100,0050,0025,002,730,91Ampere
700 Watt116,6758,3329,173,181,06Ampere
800 Watt133,3366,6733,333,641,22Ampere
900 Watt150,0075,0037,504,091,37Ampere
1000 Watt166,6783,3341,674,551,52Ampere

What converter is necessary for

Online converter allows changing current into power quickly. It allows converting the consumed current strength of 1 ampere of any consumer in watt at a voltage of 12 or 220 and 380 volts.

This power conversion is used both in the selection of an alternator for current consumers in a car’s lighter socket of 12 volts with direct current, as well as in consumer electronics when laying wiring.

Therefore, the converter for changing power to amperes or current strength to watts is necessary for each and every electrician or those who works with electricity and wants to convert these units quickly. But still the converter is mainly intended for car owners. With it, you can calculate each electrical element in a car and use the amount received to understand how much electricity an alternator should produce or what capacity of the battery is required.

How to use it

To convert current strength in amperes to power in watts, it is necessary:

  1. To enter the voltage value that supplies the source.
  2. To indicate the value of the consumed current in one field (you can choose Ampere or mA in the list).
  3. The result of current-to-power conversion will immediately appear in another field (watts are displayed by default, but you can also set kW, then the value wil be automatically converted to kilowatts).

Conversion can be performed both from amperes to watts and W to A, it is enough just to enter the consumer power, and then the consumed current strength in the network with the specified voltage will be displayed in another field.


  • How many watts in an amp?

    If we are talking about the automotive grid, there is 12 watts in one ampere at 12 volts. On a 220 volt household electrical grid, 1 amp will be equal to the 220 watt rating of the consumer, but if you are talking about a 380 volt industrial grid, then 657 watts in an amp.

  • 12 amp how many watts?

    How many watts of power at 12 amps of current consumption will depend on what voltage the consumer itself is running on the grid. So 12A it could be: 144 watts on a 12V car mains; 2640 watts on a 220V mains; 7889 watts on a 380V mains.

  • 220 watts how many amps?

    The amperage of a 220 watt consumer will vary depending on the grid it is on. It could be: 18A if the voltage is 12 volts, 1A if the voltage is 220 volts or 6A when the current consumption is on a 380 volt grid.

  • 5 amps how many watts?

    To find out how many watts a 5 amp source consumes, simply use the formula P = I * U. That is, if the consumer is plugged into a car mains where it is only 12 volts, then 5A would be 60W. When consuming 5 amps in a 220V mains supply means that the power of the consumer is 1100W. When consuming five amps on a 380V two-phase line, the power source is 3290 Watts.

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