What is crypto mining and how does it work
Crypto mining is how proof-of-work networks such as Bitcoin add new blocks: computers race to find a hash that meets a target, and the winner gets newly created coins plus transaction fees. It sounds abstract, so below you can run a tiny miner right in your browser. Then we cover difficulty, hashrate, ASIC and GPU miners, and whether mining still pays.
Mining in simple words
A blockchain needs someone to collect new transactions into a block and attach it to the chain. In proof of work, that right goes to whoever first finds a block whose SHA-256 hash starts with enough zeros. There is no shortcut: miners change a number in the block, called a nonce, and hash again, billions of times per second. The first miner to hit the target broadcasts the block, the network checks it in a fraction of a second, and the miner receives the block reward.
The work is useful for security, not for computing anything else: rewriting old blocks would require redoing all that work faster than the whole network. The basics of blocks and hashes are in what is blockchain.
Mine a block in your browser
Press start. Your browser hashes "block + nonce" with SHA-256 until it finds a hash with the chosen number of leading zeros. Every extra zero makes the search about 16 times longer.
Block#1
paused- Attempts
- 0 / ≈65536
- Speed
- 0 H/s
- Target
- 4 zeros at the start
Difficulty
Difficulty sets how small the winning hash must be. The network adjusts it so blocks keep arriving on schedule: Bitcoin aims for one block every 10 minutes on average and recalculates difficulty every 2016 blocks, roughly every two weeks. More miners join, blocks come faster, difficulty rises. Miners leave, difficulty falls.
Hashrate
Hashrate is how many hashes a device computes per second.
| Unit | Hashes per second | Typical device |
|---|---|---|
| kH/s | thousands | A browser, like the miner above |
| MH/s | millions | A phone or laptop CPU |
| GH/s | billions | A graphics card on SHA-256 |
| TH/s | trillions | One Bitcoin ASIC miner (100 to 300+ TH/s) |
| EH/s | quintillions | The whole Bitcoin network (around 1,000 EH/s) |
Estimate the output of a device with the mining calculator.
CPU, GPU and ASIC miners
- CPU: the processor in any computer or phone. Far too slow for Bitcoin, still used for a few coins designed for CPUs, such as Monero.
- GPU: graphics cards. Fast at parallel work; they mine some altcoins, but not Bitcoin profitably.
- ASIC: chips built for one algorithm only. Every Bitcoin block today is found by ASIC farms. A single unit draws 3 to 4 kW and is loud enough to need a separate room.
Mining on a phone is covered separately in crypto mining on a phone.
Pools and cloud mining
A single small miner might wait years to find a block alone, so miners join pools that combine hashrate and split rewards by contributed work. Cloud mining means renting hashrate from someone else's farm. It is a frequent cover for scams, so read cloud mining: how to spot a scam first.
Is crypto mining profitable?
For home users, rarely. Profit is the value of mined coins minus electricity, hardware, cooling and pool fees. With modern ASICs and cheap electricity it can work; with a gaming PC or a phone it usually costs more in power than it earns. Every four years Bitcoin's block reward halves, which squeezes miners further unless the price rises.
If you want the experience without the electricity bill, TotalHash is a free mining game inside Telegram. Your phone computes real SHA-256 hashes and closes blocks of the game network for the in-game token #TH, and tasks pay small amounts of USD₮ and GRAM you can withdraw to a TON wallet.
Mine blocks with your phone in a free Telegram game.
Open TotalHashQuick answers
What is crypto mining in simple terms?
Computers race to find a block hash that meets a target. The winner adds the block to the blockchain and receives new coins plus fees.
How does crypto mining work?
Miners repeatedly change a number in the block and hash it with SHA-256 until the hash has enough leading zeros. The network checks the result and rewards the miner.
What is an ASIC miner?
A device with chips built for one algorithm only, such as SHA-256 for Bitcoin. ASICs are thousands of times faster than graphics cards at that task.
Is crypto mining profitable at home?
Rarely. Electricity, hardware and cooling usually cost more than the coins a home setup earns, especially with a PC or a phone.
What is a mining pool?
A group of miners who combine their hashrate and share block rewards in proportion to the work each one contributed.