Decibel Calculator

Calculate decibels for power and voltage ratios. Convert between dB, dBm, dBW, and dBV instantly. Perfect for audio engineers, RF engineers, and electronics hobbyists. Pure client-side.

Common Reference Values

0 dBm = 1 mW
30 dBm = 1 W
60 dBm = 1 kW
0 dBW = 1 W
0 dBV = 1 V

Formulas Used

dB = 10 × log₁₀(P₂/P₁)
dB = 20 × log₁₀(V₂/V₁)
dBm = 10 × log₁₀(P/1mW)
dBW = 10 × log₁₀(P/1W)
dBV = 20 × log₁₀(V/1V)

About Decibel Calculator

The decibel (dB) is a logarithmic unit used to express the ratio of two values of a physical quantity, typically power or intensity. It is widely used in acoustics, electronics, and telecommunications. One decibel is one tenth of a bel (B). The decibel calculator supports power ratios (10×log), voltage/current ratios (20×log), and absolute units like dBm (referenced to 1 mW), dBW (referenced to 1 W), and dBV (referenced to 1 V). All calculations happen in your browser — no data is sent to any server.

Features

How to Use

  1. Select the calculation mode: Power Ratio, Voltage Ratio, dBm, dBW, or dBV
  2. Enter the reference value and measured value
  3. Choose the appropriate unit from the dropdown
  4. Click Calculate to see the result in decibels
  5. Use reverse mode to calculate a value from a known dB level

Common Use Cases