Enter any two electrical quantities (V, I, R, P) to solve for the remaining values.
Leave blank to solve for voltage. Unit: V.
Leave blank to solve for current. Unit: A.
Leave blank to solve for resistance. Unit: Ω.
Voltage
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Voltage — Calculated outcome V. Derived from your inputs via the displayed formula; use to plan.
Current
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Current — Calculated outcome A. Derived from your inputs via the displayed formula; use to plan.
Resistance
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Resistance — Calculated outcome Ω. Derived from your inputs via the displayed formula; use to plan.
What this means
Leave exactly one of voltage, current, or resistance blank. With two known values the missing one is computed directly. Providing fewer than two inputs shows dashes.
Ohm’s law links voltage, current, and resistance in a circuit: V = I × R. Enter any two values and this tool solves for the third.
Formula
V = I × R | I = V ÷ R | R = V ÷ I
Worked examples
FAQ
What if I provide all three values?
They are echoed back unchanged — the tool only replaces the single missing value.
Can I provide only one value?
No — at least two values are required for a unique answer, so the result shows dashes.