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⛏️ Proof of Work

Last verified: June 2026

Proof of Work is the original way blockchains like Bitcoin agree on who owns what — by making computers race to solve hard puzzles. Here's how it works, in plain English.

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The problem it solves

A blockchain has no boss — no bank or company deciding which transactions are real. So how do thousands of strangers' computers agree on a single shared truth, and stop someone from cheating? Bitcoin's answer, invented by Satoshi Nakamoto, is called Proof of Work. It's a way of making honesty cheaper than cheating.

How it works, simply

Computers on the network (called miners) compete to solve a very hard mathematical puzzle. The puzzle is difficult to solve but easy to check — a bit like a combination lock that takes ages to crack but a second to verify once you have the code. The first miner to solve it gets to add the next "block" of transactions to the chain and earns a reward in new coins. Then everyone starts racing on the next puzzle.

How Proof of Work mining actually works Multiple miners race to solve a puzzle. The first to solve it adds the next block and earns a reward, while everyone else's work is discarded and a new race begins. ⛏️ Miner A still solving... ⛏️ Miner B ✓ solved it first! ⛏️ Miner C still solving... Miner B adds the next block 💰 and earns the block reward A & C's work is discarded — the race restarts

Why this keeps the network honest

Solving these puzzles takes real electricity and expensive computers — real-world cost. To cheat the system (say, to fake transactions), you'd need to out-compute everyone else combined, which would cost an astronomical amount of money and energy. It's simply not worth it: you'd spend more trying to cheat than you could ever steal. That economic reality, not a referee, is what keeps Bitcoin secure.

The big downside

All that computing uses a lot of electricity — Proof of Work's energy consumption is its most criticised feature, and the main reason newer networks looked for alternatives. The most popular alternative, Proof of Stake, achieves similar security using almost no energy. But Proof of Work remains prized by Bitcoin supporters as the most battle-tested, robustly decentralised approach there is.