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 wellknown 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 3phase 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?
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 threephase, then I = P/(√3xU), since it is necessary to calculate the voltage in each phase.
P = I * U or P = √3 * I * U in case of 3phase network of 380 V.
So, if we deal with a car network of 12 volts, then 1 ampere is 12 watts, and a 220V household power supply network has the current strength of 220 watts (0.22 kW). Industrial equipment, powered by 380 volts, has 657 watts.
AmpereWatt Conversion Table
6  12  24  220  380  Volt  
5 Watt  0,83  0,42  0,21  0,02  0,008  Ampere 
6 Watt  1,00  0,5  0,25  0,03  0,009  Ampere 
7 Watt  1,17  0,58  0,29  0,03  0,01  Ampere 
8 Watt  1,33  0,67  0,33  0,04  0,01  Ampere 
9 Watt  1,5  0,75  0,38  0,04  0,01  Ampere 
10 Watt  1,67  0,83  0,42  0,05  0,015  Ampere 
20 Watt  3,33  1,67  0,83  0,09  0,03  Ampere 
30 Watt  5,00  2,5  1,25  0,14  0,045  Ampere 
40 Watt  6,67  3,33  1,67  0,13  0,06  Ampere 
50 Watt  8,33  4,17  2,03  0,23  0,076  Ampere 
60 Watt  10,00  5,00  2,50  0,27  0,09  Ampere 
70 Watt  11,67  5,83  2,92  0,32  0,1  Ampere 
80 Watt  13,33  6,67  3,33  0,36  0,12  Ampere 
90 Watt  15,00  7,50  3,75  0,41  0,14  Ampere 
100 Watt  16,67  3,33  4,17  0,45  0,15  Ampere 
200 Watt  33,33  16,67  8,33  0,91  0,3  Ampere 
300 Watt  50,00  25,00  12,50  1,36  0,46  Ampere 
400 Watt  66,67  33,33  16,7  1,82  0,6  Ampere 
500 Watt  83,33  41,67  20,83  2,27  0,76  Ampere 
600 Watt  100,00  50,00  25,00  2,73  0,91  Ampere 
700 Watt  116,67  58,33  29,17  3,18  1,06  Ampere 
800 Watt  133,33  66,67  33,33  3,64  1,22  Ampere 
900 Watt  150,00  75,00  37,50  4,09  1,37  Ampere 
1000 Watt  166,67  83,33  41,67  4,55  1,52  Ampere 
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:
 To enter the voltage value that supplies the source.
 To indicate the value of the consumed current in one field (you can choose Ampere or mA in the list).
 The result of currenttopower 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.
FAQ

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 twophase line, the power source is 3290 Watts.