1.13 The 21 Million Cap

Bitcoin's supply is capped at 21 million coins. This is not a suggestion or a target — it's a hard limit enforced by the protocol's consensus rules, which every node on the network independently verifies.

Unlike gold, where we don't know exactly how much exists underground and new mines can be discovered, Bitcoin's total supply is mathematically knowable and verifiable by anyone.

The 21 million cap is enforced by the block subsidy halving mechanism. When Bitcoin launched, each block rewarded miners with 50 bitcoins. Every 210,000 blocks (roughly 4 years), this reward is cut in half.

By 2140, all 21 million bitcoin will have been issued. After that, miners will earn revenue purely from transaction fees, and the supply will never increase again.

This absolute scarcity makes Bitcoin the first asset in history where the total supply is perfectly known, verifiable, and permanently fixed. Even gold's supply can increase with new discoveries or asteroid mining.