Bitcoin Mining: Consensus, Issuance, and the Halvings

Two jobs in one mechanism

Mining is a distributed consensus system. The protocol’s own walkthrough says it plainly: mining is used to confirm pending transactions by including them in the blockchain ^[1]. Miners assemble valid payments into blocks. They compete for the right to append the next block. The winner collects newly issued coins plus the fees inside the block ^[2].

The competition is the security. The protocol frames it as a lottery: raising the odds of winning the next block takes real work, and the lottery shape makes it difficult for any single participant to keep adding blocks one after another ^[1]. Confirmation follows. A payment included in a block usually receives its first confirmation within about ten to sixty minutes ^[1].

The issuance schedule, on the record

Issuance halves on a fixed cadence. Every 210,000 blocks, roughly four years, the new-coin reward drops by half ^[2]. Four halvings have happened, and each boundary block is a dated on-chain event, verified identically by two independent block-data providers ^[4].

November 2012. The reward fell from 50 to 25 coins. July 2016. From 25 to 12.5. May 2020. From 12.5 to 6.25. April 2024. From 6.25 to 3.125, the rate now in force ^[4]. The count matters. Four halvings is the complete list, not a sample of an ongoing series with more known dates. The next one is protocol-scheduled, not calendar-pinned, and this page does not predict its market context.

The supply count, dated

Total supply is capped at 21 million coins, in the FAQ’s own words: only 21 million bitcoins will ever be created ^[2]. Circulating supply at this site’s read was 20,083,115 coins, on 12 September 2026, per an on-chain provider’s total-supply endpoint ^[3]. Under four million coins remain to be issued, spread over the halving schedule’s long tail.

Both numbers are protocol facts with different clocks. The cap is static code. The circulating count moves with every block, so its read date is part of the figure.

The difficulty rule

As more miners participate, the protocol retargets the difficulty of the work upward, keeping block production near its intended pace ^[1]. The rule runs both ways. Miners leaving makes the work easier. The adjustment is automatic and protocol-set, with no committee. That is what makes the ten-minute block cadence a property of the system rather than a claim by its participants.

Fees, the other half of the income

Miners are paid in two streams. The block subsidy is one. The transaction fees inside each block are the other ^[2]. The subsidy halves on the schedule above. The fee stream does not follow that schedule. It follows what transactors offer to have their payments included. The mix shifts by design as the subsidy shrinks, and the mining explainer carries the mechanism in detail.

The energy question, kept attributed

Bitcoin’s energy consumption has been estimated, in work this page does not re-derive, as comparable to that of entire countries, and the environmental impact is a concern for some observers. Both halves of that sentence are attribution, not assertion. This site carries no energy estimate of its own, because the pack behind this page banks none with a source. What is banked is the framing rule. The estimate is attributed. The concern is attributed. Readers weighing the question deserve to know who holds each position, and an education page that blurred attribution into verdict would fail its own standard.

How to check the supply yourself

The circulating count above is not a privileged number. The endpoint it came from is public ^[3]. A second independent block-data provider returns the same halving boundary blocks with identical timestamps and hashes ^[4]. That is the verification posture of this whole family. Protocol facts are checkable facts. The cap sits in the software. The schedule sits in the chain. The count sits on a public endpoint. Nothing here asks to be trusted on reputation.

The page this file replaces

The prior version of this page was a stub, roughly seventy words around a video slot, with no claims worth extracting. The research pack recorded it as documented-empty and assigned the family’s substance to the child pages. This rewrite keeps that division of labor. The overview holds the schedule, the count, and the rules. The explainer holds the full mechanics. A reader who wants one page and stops here leaves with the four dated halvings, the cap, the count, and the difficulty rule. That is the floor this page owes.

The family this page opens

Three more pages complete the mining family. The what is bitcoin mining page holds the full claim-by-claim explainer, from consensus to the energy question, in the protocol’s own terms. The hardware evolution page holds the CPU to ASIC history, with the era boundaries dated where the protocol dates them. The mine page addresses the direct question people type, what it takes to mine now, in the ASIC era. This page is the overview. The children carry the depth.

Where this page sits

The bitcoin hub is this family’s home root, and the price page carries the supply schedule’s market half, the price record, with the same dating discipline on every figure.