Work out signal attenuation instantly with clear inputs, formula shown and shareable results.
Attenuation in decibels adds along a chain, which is the whole point of working in dB. Every 3 dB halves the power and every 10 dB divides it by ten, so three 6 dB stages give 18 dB total — a factor of about 63 reduction in power.
Attenuation
Pout(dBm) = Pin(dBm) - total dB; power ratio = 10^(-dB/10)
Because cascaded gains and losses simply add instead of multiplying, and the logarithmic scale spans the enormous dynamic range of RF systems compactly.
Power referenced to one milliwatt: 0 dBm is 1 mW, 30 dBm is 1 W, and -100 dBm is a typical weak receive signal.