How Bitcoin Mining Works

“Mining” is one of Bitcoin’s most misunderstood ideas. No one is digging for digital coins. Mining is really about securing the network and ordering transactions — and getting paid for it. Here’s how it works.

The job miners do

Every ten minutes or so, all the recent Bitcoin transactions need to be bundled into a block and added to the shared ledger. But who gets to add the next block, and how do we stop someone from cheating? That’s the problem mining solves.

Miners compete to solve a hard math puzzle. The puzzle has no shortcut — the only way to solve it is to try enormous numbers of guesses very quickly. The first miner to find a valid answer gets to add the next block and claims the reward. This system is called proof-of-work.

Why waste all that effort?

The “work” isn’t wasted — it’s what makes Bitcoin secure. Because adding a block requires real computing power and energy, rewriting history would require redoing all that work and out-competing the entire global network at once. That’s astronomically expensive, which is precisely the point: it makes the ledger extremely hard to tamper with.

In other words, the cost of mining is the price of trustworthy, decentralized money that no one controls.

The reward: how new bitcoin is created

The winning miner receives two things:

1. The block subsidy — newly created bitcoin. This is how all bitcoin enters circulation.
2. Transaction fees — paid by the people whose transactions are in the block.

The halving

About every four years, the block subsidy is cut in half — an event called the halving. Bitcoin launched at 50 BTC per block; through successive halvings it has dropped to 3.125 BTC as of 2024. This schedule continues until the subsidy reaches zero and the supply caps out near 21 million coins, expected around the year 2140. After that, miners are paid entirely by transaction fees.

The halving is what makes Bitcoin’s issuance predictable and steadily scarcer over time. Read more in the 21 million supply cap.

Difficulty adjustment

What if more miners join and blocks start coming faster than every ten minutes? Bitcoin automatically adjusts the puzzle’s difficulty about every two weeks to keep the average block time near ten minutes — no matter how much mining power is online. This self-correcting mechanism is one of Bitcoin’s most elegant features.

What mining looks like in practice

Today, mining is done with specialized machines called ASICs, built for nothing but this calculation. Because a single machine rarely wins blocks on its own, most miners join a mining pool to combine their power and share rewards steadily. We cover that in how to choose a mining pool.

Mining also has a real, ongoing conversation around energy — including how it increasingly uses surplus, stranded, and renewable power. See Bitcoin energy use explained.

The takeaway

• Mining orders transactions and secures the network through proof-of-work.
• Winners earn new bitcoin plus fees.
• The halving steadily reduces new supply.
• Difficulty adjustment keeps the rhythm steady.

Mining is the engine that lets a leaderless network agree on one shared history — without trusting anyone. It’s a genuinely clever solution to a very hard problem.