Ohm’s Law Calculator
Ohm’s law is V = I × R. Power is P = V × I. Enter any two of voltage, current, or resistance (leave the unknown at 0) to solve the third, then see power.
Voltage12 V
Current2 A
Resistance6 Ω
Power24 W
Educational use. Mains wiring requires a qualified electrician.
Formula
V = IR. P = VI = I²R = V²/R.
How to use this calculator
- Fill in two known values.
- Set the unknown to 0.
- Read V, I, R, and P.
Examples
12 V and 2 A
R = 6 Ω. P = 24 W.
FAQ
AC circuits?+
This is the DC / resistive form. AC with reactance needs impedance.
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