buncha/engineering/ohmslaw

Ohm's Law Calculator

What do you know?

Pick the two values you have. We'll compute the other two.

Voltage (V)

unit: V

Current (I)

unit: A

Solved

Resistance (R)

24 Ω

Power (P)

600 W

V (in)

120 V

I (in)

5 A

R (out)

24 Ω

P (out)

600 W

The four formulas

V = I × R
P = V × I
P = I² × R
P = V² ÷ R

DC math. These formulas assume direct current or purely resistive AC loads. For AC with motors, transformers, or other reactive loads, real power is P = V · I · cos(φ) where φ is the phase angle. Power factor 1.0 → these formulas are exact; power factor 0.85 (typical motor) → real power is 15% lower than V·I.

Read the guide

Ohm's Law in Practice — The Four Formulas That Run Every Circuit

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About Ohm's Law Calculator

Voltage, current, resistance, power — give us any two, we compute the other two. The wheel chart in calculator form.

Like every tool on Buncha, this one runs entirely in your browser. There's no upload, no log, no record of what you've pasted or generated. Close the tab and the data is gone.

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