RMS Voltage to Resistive Power
Conversion
Convert with explicit units, definitions and assumptions.
Formula
P = Vᵣₘₛ² / 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 use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Pure resistive load. RMS alone is not a power unit; reactive loads require impedance and phase information.
Example Calculation
Example inputs
- RMS voltage: 10 V
- Resistance: 8 Ω
10 Vrms across an 8 Ω resistor produces 12.5 W.
Frequently asked questions
How do I use this calculator?
Enter rms voltage, resistance. The result updates automatically. Use Reset to restore the example values.
What method does it use?
P = Vᵣₘₛ² / R. Pure resistive load. RMS alone is not a power unit; reactive loads require impedance and phase information.
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.