Issuance & the 21 million cap

Every fiat currency in history shared one fatal weakness: whoever controlled it could always make more. Bitcoin’s answer is a supply schedule fixed in code and known to the last coin — issued on an unstoppable, ever-shrinking timetable that no one can alter.

The halving

When Bitcoin launched, each block rewarded the miner with 50 bitcoin. Roughly every four years, that reward is cut in half — an event called “the halving”:

2009: 50 BTC per block
2012: 25 BTC
2016: 12.5 BTC
2020: 6.25 BTC
2024: 3.125 BTC — and so on, halving until it reaches zero around the year 2140.

Add up this ever-shrinking series and it converges to a hard ceiling: just under 21 million bitcoin, ever. New supply slows to a trickle and then stops. Drag the year below to watch it happen — supply climbing toward the cap as the reward halves and inflation falls away.

Circulating supply Annual inflation rate

Year

Block reward

In circulation

Of 21M mined

Annual inflation

Half of all bitcoin was issued in the first years; the curve then flattens toward its ceiling of just under 21 million, reached around 2140. Bitcoin’s inflation rate is already below gold’s — and only ever falls.

Disinflation by design

This is the mirror image of fiat. A central bank expands the money supply at its discretion, quietly taxing savers through inflation. Bitcoin’s issuance only ever slows. Its inflation rate is now lower than gold’s and keeps falling, on a schedule everyone can see decades in advance. There are no surprises, no emergency printing, no “temporary” measures that become permanent.

Predictable to the last satoshi. Nobody knows how many dollars will exist next year — that’s a political decision. Everybody already knows exactly how many bitcoin will exist in the year 2100. That certainty is the whole point: a store of value the powerful cannot dilute. It’s the hard money the Austrians wanted, finally made unbreakable.

What happens when the reward ends?

As the block subsidy shrinks toward zero, miners are increasingly paid by transaction fees instead of new coins. The security budget shifts from issuance to fees, but the incentive to mine honestly remains. The 21-million cap holds; only the way miners get paid changes.

All of this rests on one physical fact we’ve kept circling: producing bitcoin costs real energy. That isn’t a bug or an accident — it’s exactly what gives digital bits their weight. Next: energy as money.

Key takeaways

New bitcoin is issued on a fixed schedule that halves every ~4 years, capping supply at just under 21 million around 2140.
No one can vote to print more — issuance runs on math, not a central bank’s discretion.

Check yourself

What is Bitcoin’s maximum supply?

What happens to issuance roughly every four years?

Spotted an error or have feedback on this lesson? Suggest a correction ↗