⚡ EE Calcs

dB ↔ Power / Voltage Converter

Convert between dB and power or voltage ratios.

P1 / V1 input G P2 / V2 output power: dB = 10·log₁₀(P₂/P₁) voltage: dB = 20·log₁₀(V₂/V₁) +6 dB voltage = ×2 · +10 dB = ×10

Values

Result

Ratio = 3.98

Decibels

A decibel is a logarithmic ratio. For power: dB = 10·log₁₀(P₂/P₁); for voltage or amplitude: dB = 20·log₁₀(V₂/V₁). Because power ∝ V², the same physical ratio gives twice the dB value in voltage terms — e.g. +6 dB voltage = ×2, +6 dB power = ×4.

Handy anchors: +3 dB power ≈ ×2, +10 dB = ×10, −20 dB = ×0.1.