Decibel Calculator

Easily calculate and convert decibel (dB) values. Compare noise levels and convert power or voltage ratios to dB with this free online decibel calculator.

Frequently Asked Questions

What is a decibel (dB)?
A decibel is a logarithmic unit used to express the ratio of two physical quantities. It is commonly used to measure sound intensity, electronic signal strength, and communication loss.
How much louder is a 10 dB increase?
A 10 dB increase is perceived as roughly twice as loud to the human ear, while the actual acoustic energy increases by a factor of 10.
What is the difference between dBm and dBW?
dBm references 1 milliwatt (mW) and dBW references 1 watt (W). The relationship is 0 dBm = -30 dBW.
2026 physical constants