How many decibels is a loud noise?

Loudness has to do with the sensitivity of the ears of an individial. The question belongs to psycho acoustics and is not easy to answer.

Answer

Loudness depends on the volume and intensity of the sound. A deaf person cannot hear and thus has insensitive ears. Her ear insensitivity has no effect on the loudness of a nearby boombox.

A decibel is a logarithmic scale of loudness used to measure the strength or loudness of a signal. Your noise would need to be measured in order to determine its value in decibels.

A whisper is about 20 decibels. A sound measured at around 120 decibels would border on pain. Normal conversation measures at about 60-70 decibels.