Transaction Fee
blockchain · technical · basics
The amount paid to miners or validators for including a transaction and consuming scarce block space or execution resources.
- Also known as
- Network Fee, Gas Fee, Miner Fee
A transaction fee compensates block producers for including a transaction and helps allocate limited block space. When demand is high, users often raise fees to improve confirmation priority.
Fee units differ by chain. UTXO networks commonly price transactions by size, such as satoshis per byte or virtual byte, while EVM networks use gas for computation and storage.
Users can manage fees by waiting for lower congestion, batching payments, consolidating UTXOs when fees are low, using fee estimation tools, or applying RBF/CPFP where supported.
Why does a small payment sometimes have a large fee?
On Bitcoin and Bitcoin Cash, the fee usually depends on transaction size and demand for blockspace, not the amount transferred. Spending many small UTXOs can require more inputs than spending one large output. A wallet can therefore quote more for a small payment assembled from many inputs.
For a normal BTC or BCH transaction, the network fee is the total input value minus the total output value. For example, an input of 100,000 satoshis, a payment output of 60,000, and a change output of 39,500 leave a fee of 500 satoshis. Change returns to the wallet; it is not part of the fee. See the Bitcoin transaction guide for the input/output model.
The fee rate divides that fee by transaction size. Read how congestion affects confirmation for the queueing mechanism, or explore it with simulated transactions in Blockspace Lab.
Related terms
Transaction
→A serialized state transition that a blockchain can validate, relay, and include in a block.
blockchain · technical
Mining
→Proof-of-work block production in which miners build candidate blocks and search for a header hash below the network target.
mining · proof-of-work
Mempool
→A node's local set of unconfirmed transactions accepted for possible relay and block inclusion.
blockchain · node
Gas
→The metered unit of computational work on EVM chains, paid in the native token to run transfers and smart contracts.
eth · fee
Fee Rate
→Transaction fee per unit of size: commonly sat/vB for Bitcoin or sat/byte for Bitcoin Cash. It helps explain miner selection, not a guaranteed wait.
blockchain · economics
Batching
→Constructing one transaction with outputs for multiple payments so transaction overhead is shared.
wallet · efficiency