Ohm's Law Calculator
Solve any of V, I, R and get power automatically.
Amortization schedule
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Showing first 12 of months.
Growth over time
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Introduction
Ohm's Law Calculator — Solve any of V, I, R and get power automatically. Enter Voltage (V) — leave blank if unknown, Current (A) — leave blank if unknown, Resistance (Ω) — leave blank if unknown to get an instant, accurate result.
Formula
Ohm's law: V = I × R. Power: P = V × I. Enter any two of V, I, R to solve for the third.
Step-by-step
- Enter the Voltage (V) — leave blank if unknown.
- Enter the Current (A) — leave blank if unknown.
- Enter the Resistance (Ω) — leave blank if unknown.
- Click Calculate to see your result instantly.
Real-world example
Example: With Voltage (V) — leave blank if unknown = 12, Current (A) — leave blank if unknown = 2, the Ohm's Law Calculator gives V: 12, I: 2, R: 6.
Frequently Asked Questions
How many values do I need to provide?
Exactly two of voltage, current, and resistance — the third is solved for automatically.
How is power calculated?
P = V × I, once voltage and current are both known.
What inputs does the Ohm's Law Calculator need?
You'll need to provide: Voltage (V) — leave blank if unknown, Current (A) — leave blank if unknown, Resistance (Ω) — leave blank if unknown. All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Ohm's Law Calculator?
The Ohm's Law Calculator applies the formula exactly as calculated — Ohm's law: V = I × R. Power: P = V × I. Enter any two of V, I, R to solve for the third. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Ohm's Law Calculator free to use?
Yes, the Ohm's Law Calculator is completely free, requires no signup, and runs instantly in your browser.
About the Ohm's Law Calculator
The Ohm's Law Calculator uses a real, verifiable formula — Ohm's law: V = I × R. Power: P = V × I. Enter any two of V, I, R to solve for the third. — so results are accurate every time, not an approximation.