Decibel Scale

How to Use

• Ratio slider — set a linear ratio (0.001–1000); the dB value is calculated instantly.
• dB slider — enter a dB value directly; the equivalent ratio is shown.
• Voltage / Power buttons — switch between 20·log and 10·log formulas.
• The right panel shows a vertical SPL scale with real-world audio reference levels color-coded by hearing risk.

What to Observe

• +6 dB doubles voltage; +20 dB multiplies voltage by 10.
• +3 dB doubles power; +10 dB multiplies power by 10.
• The two formulas differ because power scales as voltage squared.
• Levels above 85 dB SPL can cause hearing damage over prolonged exposure (shown in orange/red).

Key Equations

\[dB_{voltage} = 20\log_{10}\!\left(\frac{V_2}{V_1}\right)\]

\[dB_{power} = 10\log_{10}\!\left(\frac{P_2}{P_1}\right)\]