Transaction fees in cryptocurrency are small charges imposed by blockchain networks to process and validate transactions. These fees compensate miners (in Proof-of-Work systems) or validators (in Proof-of-Stake systems) for securing the network and adding transactions to the blockchain.

The fee amount depends on network congestion, transaction size (in bytes), and priority. For example, Bitcoin and Ethereum fees rise during high demand as users compete for block space. Ethereum also uses a gas fee system, where complex operations (like smart contracts) cost more than simple transfers.

Some blockchains (e.g., Solana, Binance Smart Chain) offer lower fees, while others (like Bitcoin during peak times) can become expensive. Users can often adjust fees, paying more for faster confirmation or less if they’re willing to wait.

Exchanges may also charge additional withdrawal fees, separate from blockchain costs. Understanding transaction fees helps traders optimise costs, especially for frequent or high-volume transfers. Some newer networks aim for near-zero fees, but security and decentralisation trade-offs remain key considerations.

In summary, crypto transaction fees are essential for network functionality, varying by blockchain, demand, and transaction type, making them a critical factor for traders and investors.