Volts, Amps, Watts & Ohms Calculator

Convert between Volts, Amps, Watts Calculator. Here is the answer to the question:5/8 as percent or how to convert 5/8 to percent.

Watts, Volts, Amps & Ohms Calculator

Fill in any two of the fields then, click on the button 'calculate'.
Power (watts):
Voltage (volts):
Current (amps):
Resistance (ohms):


Please fill in two of the four fields above.

Using this converter you can make any of these calculations: watts to ohms, watts to amps, watts to volts, volts to watts, volts to amps, volts to ohms, amps to volts, amps to watts, amps to ohms, ohms to volts, ohms to watts and ohms to amps. Just fill in one of these units pairs in the calculator above.

Electrical units definitions

We are going to define these electrical units (amperes, volts and watts) by imagining the electric current as the water that flows through a pipe. It it is often called electronic–hydraulic analogy.

Ampere or amp

Ampere measures the electrical current, the current represents the speed at which the electricity flows. Ampere would be the volume of water that flows through the pipeline per second. Ampere would be used to measure how fast the water flows through the pipeline. Ampere is often shortened to "amp".


Volt measures the voltage, volts represent the electrical potential difference. Volts would be the water pressure difference across the pipe. The greater the pressure the greater the voltage.


Watt measures the electrical power. Wattage corresponds to the amount of energy that an electric device uses per second. Watts would be the power the water could provide, for example to a mill wheel.


Ohms is a unit of electrical resistance, the greater the resistense the more difficult it is for current to flow. Using the electronic–hydraulic analogy, we coud say that a pipe having a diameter of 10 inches would have a smaller resistance than a pipe of one inch.

Electrical Calculation Formulas

Watt calculation / conversion formulas:

Formulas to calculate watts from volts, amps and ohms.

watts = volts² / ohms

watts = amps² * ohms

watts = volts * amps

Volt calculation / conversion formulas:

Formulas to calculate volts from watts, amps and ohms.

volts = watts * ohms 

volts = watts / amps

volts = amps * ohms

Amp calculation / conversion formulas:

Formulas to calculate amps from watts, volts and ohms.

amps = volts / ohms

amps = watts / volts

amps = watts / ohms 

Ohms calculation / conversion formulas:

Formulas to calculate ohms from watts, amps and volts.

ohms = volts / amps

ohms = volts² / watts

ohms = watts / amps²

Ohms Law Pie Chart

To help us understand the the relationship between the various units, we can take all of the equations from above and condense them into a simple Ohms Law pie chart as shown below.

Power Wheel


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