What is a block reward in crypto
A block reward is the compensation a blockchain network gives to the participant who successfully adds a new block of transactions to the chain. It has two parts: the block subsidy and the transaction fees. The subsidy is newly minted tokens. The fees are what users pay to have their transactions included.
The block subsidy is the predictable part, set by the network's code and following a fixed emission schedule. On Bitcoin, the subsidy started at 50 BTC per block and halves roughly every four years; as of the 2024 halving, it is 3.125 BTC. On proof-of-stake chains like Ethereum, the subsidy is paid as an attestation reward to validators who propose and vote on blocks. These rewards are smaller per validator but accumulate over time.
Transaction fees are the variable piece. Every transaction competes for limited block space, and users bid a base fee plus an optional priority fee - sometimes called a tip - to get their transaction processed faster. On Ethereum, the base fee is burned, not paid to the validator, while the priority fee goes directly to the validator. On Bitcoin, the miner collects the entire fee amount.
There is a third layer to fees on some chains: maximal extractable value, or MEV. Validators and searchers can reorder, insert, or censor transactions within a block to capture additional profit. This is common on Ethereum, where bots bid for block space to execute arbitrage or liquidations. MEV is not a formal part of the block reward. But it often ends up in the validator's wallet.
The total block reward differs sharply between proof-of-work and proof-of-stake systems.
On Bitcoin, miners spend electricity and hardware to solve a cryptographic puzzle. The winner gets the full block reward: the subsidy plus all transaction fees in that block. If fees are low, the subsidy still covers the miner's cost. If fees spike - such as during a mempool backlog - the reward can double or triple, but the subsidy dominates for now. Miners are paid in Bitcoin. They must sell or borrow against it to cover electricity bills.
On Ethereum, validators do not mine. They lock up 32 ETH as collateral and are randomly selected to propose a block, and the reward is split into several pieces. First is the attestation reward, paid for correctly voting on other validators' blocks. Second is the block proposal reward, a small fixed subsidy. Third is the priority tips from transactions in that block. Fourth is any MEV extracted from those transactions. A proposer might earn 0.01 - 0.05 ETH in a typical slot, but that varies massively. The subsidy component is modest; tips and MEV tend to be the bulk of income.
The reward per block declines over time because emission schedules decay. Bitcoin's subsidy halves every 210,000 blocks. That is a hard cap: only 21 million BTC will ever exist, and after the final halving around 2140, miners will earn only fees. Ethereum's emission schedule is not capped in the same way, but it is designed to shrink. Since the 2022 merge, new ETH issuance dropped by about 90 percent. The network now targets a net-zero or slightly negative issuance when fee burning outpaces new rewards.
The consequence is that block rewards are not stable. In 2010, a single Bitcoin block paid 50 BTC. In 2025, that same block pays roughly 3.125 BTC plus fees. The purchasing power of each Bitcoin has grown, but the nominal reward is far smaller. On Ethereum, a validator who earned 8 percent annual yield in 2022 might see 3 - 5 percent in 2025 as tip competition falls and subsidy shrinks.
This decay shapes miner and validator behavior. High-cost miners drop out after halvings. Validators may exit if yield drops below the opportunity cost of locked capital. The network security model depends on the total value of the block reward staying high enough to deter attacks. If fees alone cannot sustain it, the chain becomes vulnerable.
Understanding the block reward means separating subsidy from fees, and recognizing that both are moving targets. The subsidy follows a known decay curve. Fees are market-driven and unpredictable. On Bitcoin, the subsidy dominates for now; on Ethereum, tips and MEV already matter more. In the long run, every proof-of-work chain faces the same question: will transaction fees replace the subsidy when it runs out? Nobody knows. The code just keeps running.
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