An average microphone (excluding lavalier microphones) will weigh around 421g. Different types of microphones, however, weigh different. Broadcast microphones are generally, the heaviest, while handheld microphones are usually lightweight.
Here is a table that summarizes the average weights of different types of microphones.
|Microphone Type||Average weight||Minimum Weight||Maximum weight||Sample size|
|All||421g||80g (Neumann KM184 MT)||860g (Rode NT2A)||81|
|Dynamic||450g||170g (Electro Voice 635 NDB)||745g (Rode Procaster)||30|
|Condenser||433g||80g (Neumann KM184 MT)||860g (Rode NT2A)||46|
|Handheld||257g||170g (Electro Voice 635 NDB)||396g (Sennheiser e 965)||18|
|Broadcast||637g||383g (Heil Sound PR40)||745g (Rode Procaster)||8|
|USB||418g||254g (HyperX QuadCast)||680g (Samson C01)||14|
Dynamic microphones are generally quite heavy due to magnets placed inside of them.
Nevertheless, you will find out that most handheld microphones (most of them are dynamcis) are quite low weight as they are intended for use on-stage, averaging 257g.
However, at another end of a spectrum, we have broadcast microphones which average 637g in terms of weight and are generally used within broadcast studios and radios. They do not need to be moved often, so I suppose extra weight doesn’t bother anyone.
Comparing dynamic to condenser microphones, a dynamic microphone on average weighs slightly more than a condenser due to aforementioned magnets withing them.
However you will find condensers to vary from very low-end to very high-end of a spectrum. Some of them are extremely heavy if you include permanently attached stand.
USB microphones on average weigh 418g, very similar to what an average microphone would weigh regardless of their type. Most of the USB microphones are condensers and only a few of them are dynamics.
Also, lower quality USB microphones often don’t give information about their weight, therefore, you might find lacking information about budget USB microphones’ weight, which most of the time are plasticky and quite lightweight.
You can find most microphones and their weight in this article: https://voiceovertip.com/microphone-buying-guide/