Decibel Converter
Convert decibels to power ratio, voltage ratio and nepers — type one value and see the equivalent in every unit, useful for audio, telecom and engineering work.
Result will appear here.
How to use
- Enter a value or select an option.
- Choose the From and To units — the result updates live.
- See the converted values in all units below.
Note: for power, dB = 10 log10(ratio); for voltage, dB = 20 log10(ratio). 1 Np = 8.686 dB.
Tips
- For power, dB = 10 × log₁₀(ratio); for voltage or current, dB = 20 × log₁₀(ratio).
- A 3 dB gain doubles power; a 10 dB gain multiplies it by 10.
- Negative dB values just mean the ratio is below 1 — that is normal.
Frequently Asked Questions (FAQ)
What does the decibel converter do?
Enter a decibel value or a ratio and convert it instantly between power ratio, voltage ratio and nepers.
How does the conversion work?
Type a value and choose the direction - dB to ratio or ratio to dB - then see the equivalent in power ratio, voltage ratio and nepers instantly.
What is the difference between power and voltage decibels?
For power, dB = 10 x log10(ratio); for voltage or current, dB = 20 x log10(ratio). And 1 neper equals 8.686 dB.
What does a negative dB value mean?
It just means the ratio is below 1 - a value smaller than the reference. That is normal, not an error.