The dust limit is a built-in policy in Bitcoin Core that considers outputs smaller than a certain amount non-standard, thus refusing to relay them. The exact figure varies by output script type (legacy, SegWit, etc.), but typically sits around a few hundred satoshis.

While it’s not a consensus rule—nodes can override their policy—most of the network adheres to these defaults. This prevents spam transactions from cluttering the chain with near-worthless outputs, saving space for more meaningful activity. Users sending outputs below the dust limit will likely see the transaction rejected by standard nodes.