Bitcoin’s Supply Falls Short of 21 Million Through Rounding and Unclaimed Rewards
Summary
The article explains why Bitcoin’s eventual supply is below the often cited 21 million cap. Because rewards are paid in whole satoshis and halving uses integer rounding, the scheduled issuance itself ends slightly below that figure. The article then distinguishes this design effect from coins that were never issued because miners claimed less than the reward and fees available in a block.
It describes checking coinbase transactions against expected block rewards and transaction fees to identify underclaimed issuance. It gives examples of blocks with missing satoshis and reports an estimated cumulative shortfall from such blocks, which further lowers the maximum attainable supply. The analysis attributes these cases mainly to mining software bugs and says the lost issuance cannot be recovered once later ledger entries confirm the smaller payout. The figures are based on the article’s data analysis and are negligible relative to the supply overall; they do not include coins lost through owners’ mistakes or deliberately invalid addresses, which the article treats separately.
Key ideas
- Integer rounding of halving rewards means scheduled issuance ends below 21 million bitcoins.
- Miners can claim less than the available block reward and fees, permanently reducing issued supply.
- Coinbase outputs and transaction fees can be compared to estimate whether a block underclaimed its reward.
- The article attributes underclaimed rewards to historical mining software bugs and says confirmed shortfalls cannot be reclaimed.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.