Convert between power/voltage ratios and decibels. Antenna gain references are shown separately for dBi and dBd.
Calculated Gain/Loss:
Antenna Gain (Isotropic): dBi
Antenna Gain (Dipole): dBd
Power Gain (linear):
Voltage Gain (linear):
dBi is referenced to an isotropic radiator. dBd is referenced to a half-wave dipole and is 2.15 dB lower than the same antenna measured in dBi.
Equivalent Gain:
Power Ratio (Linear):
Power Ratio (relative to Dipole):
Voltage Ratio (Linear):
Definitions:
• dB: Logarithmic ratio of power (10 · log₁₀) or voltage (20 · log₁₀).
• dBi: Antenna gain relative to an isotropic radiator (theoretical spherical point source).
• dBd: Antenna gain relative to a resonant half-wave dipole. Convert to dBi by adding 2.15 dB (0 dBd = 2.15 dBi).