Bitcoin Supply and the Halving

The issuance rule

Each valid block may include newly issued bitcoin up to the current subsidy plus transaction fees. The subsidy halves every 210,000 blocks, producing a supply curve that asymptotically approaches 21 million. <strong>What halves.</strong> The event cuts the new-coin block subsidy in half. Existing balances are untouched, transaction capacity does not double and the market price is not programmed to rise.

<strong>Mining after subsidies.</strong> As issuance declines, fees are expected to become a larger share of miner revenue. The long transition gives users, miners and the fee market decades to adapt rather than imposing a sudden cutoff.

Keep in view: The halving changes new issuance, not existing coins.

Calculate one subsidy era

Between block 840,000 and block 1,049,999, the maximum subsidy is 3.125 BTC per valid block. At the target average of 144 blocks per day, that is about 450 new BTC per day before considering variation in block timing. At block 1,050,000 the subsidy becomes 1.5625 BTC, so the same target pace would issue about 225 BTC per day.

Existing balances and the transaction rules do not change. The calculation explains what the halving controls and what it does not. The exact event is determined by block height, while the calendar date is an estimate. Miner revenue also includes transaction fees, and market price is formed outside the protocol.

A claim that the halving guarantees a price outcome adds an assumption that the issuance rule itself never makes.

Keep in view: A known schedule does not dictate a market price.

The schedule, block by block

The subsidy started at 50 BTC per block in January 2009. It halved at block 210,000 in November 2012 to 25, at 420,000 in July 2016 to 12.5, at 630,000 in May 2020 to 6.25, and at 840,000 in April 2024 to 3.125. The next halving at block 1,050,000 is expected in 2028.

The sequence continues until the subsidy rounds to zero satoshis around 2140, by which point about 20,999,999.98 BTC will have been issued. Because issuance is a function of block height, not calendar time, the dates drift with block timing but the amounts never do.

Keep in view: Miner revenue gradually shifts toward transaction fees.

Where the supply is today

Roughly 19.9 million BTC had been issued by 2025, about 95 % of the eventual total, with the remaining 5 % spread over more than a century. Some of the issued coins are gone: outputs untouched since 2010 and known burned addresses suggest millions of BTC are permanently lost, though nobody can measure it directly.

Circulating supply figures on price sites count every issued coin, including lost ones, and differ slightly by method. The supply explorer on this site calculates issuance at any block height from the schedule itself rather than from a third-party estimate.

What a halving does and does not do

A halving cuts the flow of new coins to miners in half overnight, which halves the sell pressure from miners covering costs and, all else equal, raises the difficulty-adjusted cost of producing a coin. It does not change the price by rule; the market does that, and past cycles show gains that began before or long after the event.

It does change miner economics: revenue falls immediately while costs do not, and less efficient operations shut down until difficulty adjusts. Over the long run halvings shift miner income from subsidy to fees, which is the open question about Bitcoin's security budget that the fee market must eventually answer.