What formulas does this calculator use?

When voltage is provided: R = V² / P (where P is in watts). When current is provided: R = P / I². The kilowatt value is multiplied by 1000 to convert to watts before applying either formula.

Why do I need to provide voltage or current as well?

Resistance cannot be determined from power alone. Ohm's Law (V = I × R) combined with P = V × I means you need at least two of the three electrical quantities to solve for the third.

What is the difference between the two calculation modes?

Use the Voltage mode when you know the supply or load voltage. Use the Current mode when you know the operating current. Both yield resistance in ohms from the same underlying physics.

Can I enter decimal kilowatt values?

Yes. Any positive decimal value is accepted — for example, 0.5 kW (500 W) or 2.75 kW are both valid inputs.

Does this work for AC circuits?

For purely resistive AC loads the result is accurate. For inductive or capacitive loads the result represents impedance magnitude, not pure resistance. Use it as an approximation for resistive loads.

How do I convert milliwatts or megawatts?

Convert to kilowatts first: 500 mW = 0.0005 kW; 1 MW = 1000 kW. Then enter the kilowatt value in the calculator.

How much power does a 1-ohm resistor dissipate?

Power depends on the applied voltage or current, not resistance alone. For a 1 Ω resistor: at 12 V, P = V²/R = 144 W; at 2 A, P = I²R = 4 W. Use this tool to size resistance for a target power instead.

Kilowatts to Ohms Calculator

Convert kilowatts to ohms using Ohm's Law — enter power in kW with either voltage or current to find resistance.

Enter Values

Power (kW) *

1 kW = 1000 W

Calculate using

Voltage (V)

Enter power in kW and voltage or current, then click Calculate.

Resistance

0 Ω

Formula Applied

Parameter	Value

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Summary

This calculator converts kilowatts (kW) to ohms (Ω) using the power and Ohm's Law formulas. Provide power in kilowatts along with either voltage in volts or current in amps to instantly compute resistance. The tool supports both calculation paths: R = V² / P and R = P / I².

How it works

Enter the power value in kilowatts (kW).
Choose your known second variable: voltage (V) or current (A).
Enter the voltage in volts or current in amps.
Click Calculate to apply the appropriate formula.
The result shows resistance in ohms along with a full breakdown of all quantities.
Use the Copy Result button to copy the output to your clipboard.

Use cases

Determine the impedance of a high-power resistive load given its rated kilowatt output and supply voltage.
Size heating elements by calculating their resistance from rated power and operating current.
Verify motor winding resistance from nameplate kilowatt and voltage ratings.
Convert generator or inverter output power specs to equivalent load resistance.
Design power distribution circuits by matching load resistance to source capability.
Cross-check measured resistance values against calculated values for troubleshooting.
Estimate cable or conductor resistance impact on high-power circuits.
Validate thermal dissipation in power resistors from kW and current ratings.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu