Formula
- 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.
- Uses sensitivity per milliwatt, not per volt. Resistive impedance approximation; no listening-safety recommendation or acoustic calibration.
Example Calculation
- Sensitivity: 100 dB SPL at 1 mW
- Target sound level: 90 dB SPL
- Impedance: 32 Ω
100 dB SPL/mW sensitivity needs 0.1 mW for the modeled 90 dB target; at 32 Ω this is about 0.0566 V RMS.
Frequently asked questions
How do I use this calculator?
Enter sensitivity, target sound level, impedance. The result updates automatically. Use Reset to restore the example values.
What method does it use?
mW=10^((target−sensitivity)/10); RMS voltage=√(mW × impedance/1000).. Uses sensitivity per milliwatt, not per volt. Resistive impedance approximation; no listening-safety recommendation or acoustic calibration.
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.