Electronics
Ohm’s law calculator
Enter any 2 of U, I, R → voltage, current, resistance and power.
- Instant
- Free
- Private (processed locally)
- No sign-up
Calculate with Ohm’s law
Enter two values among voltage U, current I and resistance R. The tool derives the third quantity and computes power P.
The formulas
- U = R × I
- I = U / R
- R = U / I
- P = U × I
Example
| Known | Computed |
|---|---|
| U = 12 V, I = 2 A | R = 6 Ω |
| Power | P = 24 W |
100% local calculation, no data sent.
Frequently asked questions
What is the Ohm’s law formula?
U = R × I: voltage (volts) equals resistance (ohms) times current (amperes).
How do I calculate power?
P = U × I (watts). You can also write P = R × I² or P = U² / R.
How many values must I enter?
Two are enough: with two of the three quantities (U, I, R), the tool computes the third and the power.
Which units should I use?
Volts (V) for voltage, amperes (A) for current, ohms (Ω) for resistance, watts (W) for power.