What Is the General Algorithm Miners Use to Select Transactions for a Block?

Miners generally employ a greedy algorithm to select transactions, prioritizing those that offer the highest fee rate, typically measured in satoshis per virtual byte (sat/vbyte). They iterate through their mempool, selecting transactions from highest fee rate to lowest.

This process continues until the block is full, meaning the block size or weight limit is reached. The goal is to maximize the total transaction fees collected in the block, thereby maximizing the miner's profit from the block space.