Voltage
V = I × R
Find voltage by multiplying current and resistance.
The foundation of electronics
Ohm's Law
The relationship between voltage, current, and resistance — explained simply, calculated instantly.
V
=
I
×
R
V Voltage (Volts)
I Current (Amps)
R Resistance (Ohms)
What is Ohm's Law?
Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them.
Current
I = V ÷ R
Find current by dividing voltage by resistance.
Resistance
R = V ÷ I
Find resistance by dividing voltage by current.
Interactive Calculator
Enter any two values — the third is calculated automatically.
Result
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Quick Reference
Common SI prefixes used with voltage, current, and resistance.
| Prefix | Symbol | Multiplier | Example |
|---|---|---|---|
| Mega | M | × 1,000,000 | 1 MΩ = 1,000,000 Ω |
| Kilo | k | × 1,000 | 1 kΩ = 1,000 Ω |
| (base) | — | × 1 | 1 A, 1 V, 1 Ω |
| Milli | m | × 0.001 | 1 mA = 0.001 A |
| Micro | µ | × 0.000001 | 1 µA = 0.000001 A |