What Miners Actually Do
Bitcoin miners have one job: find a number that makes a hash meet certain criteria. That's it. They take a block of transactions, add a random number (the "nonce"), hash everything, and check if the result starts with enough zeros.
If not, they increment the nonce and try again. And again. Billions of times per second, across millions of machines worldwide, until someone gets lucky.
The Mining Race
Every ~10 minutes, miners worldwide race to find the next valid block. More hashrate = more guesses = better odds. Watch how hashrate translates to winning probability:
Mining Race Simulator
Watch miners compete to find the next block. Hashrate determines odds, but luck determines the winner.
Notice how the solo miner's bar barely moves? With 335 TH/s against 700+ EH/s network hashrate, your odds of winning any given block are about 1 in 2 billion. But someone wins every block.
Building a Block
Before mining, miners construct a block template—a candidate block containing transactions they want to include. The template has:
The miner hashes this header repeatedly, incrementing the nonce each time, until the hash meets the difficulty target. The nonce is the only part that changes rapidly—billions of times per second.
The Block Reward
The winning miner gets to claim the block reward: newly created bitcoin plus all transaction fees from the block.
The subsidy halves every 210,000 blocks (~4 years). It started at 50 BTC in 2009, is now 3.125 BTC, and will eventually reach zero. At that point, miners will be rewarded only through transaction fees.
| Era | Block Subsidy | Approximate Years |
|---|---|---|
| 1 | 50 BTC | 2009-2012 |
| 2 | 25 BTC | 2012-2016 |
| 3 | 12.5 BTC | 2016-2020 |
| 4 | 6.25 BTC | 2020-2024 |
| 5 | 3.125 BTC | 2024-2028 |
| 6 | 1.5625 BTC | 2028-2032 |
Why Mining Matters
Mining isn't just about creating new coins. It serves critical functions:
| Function | How Mining Provides It |
|---|---|
| Transaction Processing | Miners include transactions in blocks, confirming them |
| Security | The energy spent makes attacks prohibitively expensive |
| Coin Distribution | New bitcoin goes to those who secure the network |
| Timestamping | Blocks create an immutable record of when transactions occurred |
| Decentralization | Anyone can mine; no permission needed |
Frequently Asked Questions
Who decides which miner finds the block?
Pure probability. With 100 EH/s (exahashes per second) network hashrate, any given miner has a chance proportional to their share. It's like a lottery with better odds for more tickets.
What happens to stale blocks?
They're discarded. When two miners find blocks at nearly the same time, only one gets built upon. The other becomes a "stale block" and earns nothing—centralizing pressure is why pools prefer lower latency.
Can I mine Bitcoin at home?
Technically yes, but profitably no. ASIC miners cost thousands and consume serious electricity. At current difficulty, solo mining is essentially a lottery—the expected return is less than the electricity cost.