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Resistor Power from Voltage: Voltage magnitude Calculator

Resistor Power from Voltage: Calculate voltage magnitude from Power magnitude, Resistance. Check the formula, input units and worked result on this page.

Enter your values

W
Formula symbol: P. Required unit: W. Must be greater than zero.
Ω
Formula symbol: R. Required unit: Ω. Must be greater than zero.

Use a decimal point, without thousands separators.

This model uses positive magnitudes. Voltage and resistance belong to the same ohmic element. This form solves only missing voltage or resistance.
Example result
Voltage magnitude
7.5 V

The initial result uses the example values. Enter your own values and calculate again.

Edit inputs

How it works

Use resistor power from voltage with the units stated beside the fields. This form solves for voltage magnitude; enter the known quantities in Power magnitude, Resistance.

Inputs and units
Resistor Power from Voltage: Voltage magnitude Calculator · Inputs and units
InputExample valueWhat to enter
Power magnitude15 WFormula symbol: P. Required unit: W. Must be greater than zero.
Resistance3.75 ΩFormula symbol: R. Required unit: Ω. Must be greater than zero.
U = ((P / (1 × (R)^(-1))))^(0.5)

Worked example

Show example inputs and results

This example is generated by the same calculation engine using the starting values in the form. Your own inputs produce your own result.

Power magnitude
15 W
Resistance
3.75 Ω

Complete example results

Voltage magnitude
7.5 V

Reading the result

The result solves for voltage magnitude from the entered quantities. Check the result unit and the formula conditions before using it.

Questions and answers

Can I use the example values for my own calculation?

The example values illustrate the calculation. Replace every input with your own information, especially dates, rates and the selected operation.

When can I use the voltage magnitude result?

This model uses positive magnitudes. Voltage and resistance belong to the same ohmic element. This form solves only missing voltage or resistance.

Why are some results rounded?

Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.

Are my inputs sent to a server?

The calculator processes inputs in your browser. Its code does not send your values to a server.

Method sources: openstax.org

Methods & accuracy

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