Ohm’s Law Calculator
Physics
Find current and power from voltage and resistance.
Formula
I = V / R; P = V² / R
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations retain full precision.
- For an ideal resistive load.
Example Calculation
Example inputs
- Voltage: 12 V
- Resistance: 6 Ω
12 V across 6 Ω produces 2 A and 24 W.
Frequently asked questions
How do I use this calculator?
Enter voltage, resistance. The result updates automatically. Use Reset to restore the example values.
What method does it use?
I = V / R; P = V² / R. For an ideal resistive load.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.