Ohms Volts Watts Amps Converter Based on Ohms Law Pie Chart

Ohms Volts Watts Amps Converter Sign

This converter will calculate any two of the four electrical values (ohms, volts, watts, or amps) from the other two. Plus, each result includes the Ohm's Law formula used and the steps to solving it.

You can also enter each electrical value in 3 optional prefix units (milli, kilo, and mega). Then, once a calculation is complete (all four fields contain values), prefix selection changes will convert the new selection's corresponding value.

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Ohms Volts Watts Amps Converter

Convert two known electrical values into the other two values, and see the Ohm's Law formula used and its step-by-step solution.

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Selected Data Record:

A Data Record is a set of calculator entries that are stored in your web browser's Local Storage. If a Data Record is currently selected in the "Data" tab, this line will list the name you gave to that data record. If no data record is selected, or you have no entries stored for this calculator, the line will display "None".

DataData recordData recordSelected data record: None
Enter any 2 of the 4 values below:

Instructions:

Enter any 2 of the 4 electrical values and click the "Calculate Unknowns" button to fill in the other two. Note that once the calculation is completed (all four fields have values), changing any of the dropdown selections will convert the corresponding value to the new selection (volts to millivolts, watts to kilowatts, etc.).

Power (W):

Power (W):

If known, enter the watts in the selected units. Click the "C" button to clear a previously calculated value.

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Voltage (V):

Voltage (V):

If known, enter the volts in the selected units. Click the "C" button to clear a previously calculated value.

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Current (I):

Current (I):

If known, enter the amps in the selected units. Click the "C" button to clear a previously calculated value.

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Resistance (R):

Resistance (R):

If known, enter the ohms in the selected units. Click the "C" button to clear a previously calculated value.

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Unknown value:

Unknown value:

This result will be the first of the unknown values, and will be labeled appropriately after the calculation.

Unknown value:

Unknown value:

This result will be the second of the unknown values, and will be labeled appropriately after the calculation.

If you would like to save the current entries to the secure online database, tap or click on the Data tab, select "New Data Record", give the data record a name, then tap or click the Save button. To save changes to previously saved entries, simply tap the Save button. Please select and "Clear" any data records you no longer need.

Help and Tools

Learn

Ohms Law formula wheel and calculation examples.

Ohms Law Wheel

The Ohms Law Calculator bases its calculations on the following ohms law pie chart.

Ohm's Law Wheel

To use the ohm's law formula wheel, find the variable you wish to solve within the inner circle, and then choose the formula within that quadrant based on which two variables are known.

Ohm's Law Calculations Examples

The following ohms law calculation examples are based on the following values:

Watts:432
Volts:36
Amps:12
Ohms:3

Find Amps from Watts and Volts:

Amps=Watts / Volts
Amps=432 watts / 36 volts
Amps=12

Find Ohms from Watts and Volts:

Ohms=Volts2 / Watts
Ohms=36 volts2 / 432 watts
Ohms=1296 / 432
Ohms=3

Find Volts from Watts and Amps:

Volts=Watts / Amps
Volts=432 watts / 12 amps
Volts=36

Find Ohms from Watts and Amps:

Ohms=Watts / Amps2
Ohms=432 watts / 12 amps2
Ohms=432 watts / 144 amps
Ohms=3

Find Volts from Watts and Ohms:

Volts=Watts * Ohms
Volts=432 watts * 3 ohms
Volts=1296
Volts=36

Find Amps from Watts and Ohms:

Amps=Watts / Ohms
Amps=432 watts / 3 ohms
Amps=144
Amps=12

Find Watts from Volts and Amps:

Watts=Volts * Amps
Watts=36 volts * 12 amps
Watts=432

Find Ohms from Volts and Amps:

Ohms=Volts / Amps
Ohms=36 volts / 12 amps
Ohms=3

Find Watts from Volts and Ohms:

Watts=Volts2 / Ohms
Watts=36 volts2 / 3 ohms
Watts=1296 / 3
Watts=432

Find Amps from Volts and Ohms:

Amps=Volts / Ohms
Amps=36 volts / 3 ohms
Amps=12

Find Watts from Amps and Ohms:

Watts=Amps2 * Ohms
Watts=12 amps2 * 3 ohms
Watts=144 * 3
Watts=432

Find Volts from Amps and Ohms:

Volts=Amps * Ohms
Volts=12 amps * 3 ohms
Volts=36

Adjust Calculator Width:

Move the slider to left and right to adjust the calculator width. Note that the Help and Tools panel will be hidden when the calculator is too wide to fit both on the screen. Moving the slider to the left will bring the instructions and tools panel back into view.

Also note that some calculators will reformat to accommodate the screen size as you make the calculator wider or narrower. If the calculator is narrow, columns of entry rows will be converted to a vertical entry form, whereas a wider calculator will display columns of entry rows, and the entry fields will be smaller in size ... since they will not need to be "thumb friendly".

Show/Hide Popup Keypads:

Select Show or Hide to show or hide the popup keypad icons located next to numeric entry fields. These are generally only needed for mobile devices that don't have decimal points in their numeric keypads. So if you are on a desktop, you may find the calculator to be more user-friendly and less cluttered without them.

Stick/Unstick Tools:

Select Stick or Unstick to stick or unstick the help and tools panel. Selecting "Stick" will keep the panel in view while scrolling the calculator vertically. If you find that annoying, select "Unstick" to keep the panel in a stationary position.

If the tools panel becomes "Unstuck" on its own, try clicking "Unstick" and then "Stick" to re-stick the panel.