What is a Bitcoin block
A Bitcoin block is a batch of transactions the network accepts together, plus a short header that ties that batch to the block before it. The target time for a new block is about ten minutes.
What the batch holds
The header is 80 bytes. It carries a version, the hash of the previous block, a Merkle root, a time, the difficulty target, and a nonce. The Merkle root is one hash built by pairing every transaction hash in the block until a single value is left. Change, drop, or reorder any transaction and that root changes, so the header no longer matches the batch. The body under the header is the list of transactions. The first one is the coinbase, which pays the miner. The rest are payments people have sent.
The link to the previous block is why the history is a chain. Rewriting an old batch means redoing that block and every block after it, while the rest of the network keeps extending the chain they already have. The work that earns the right to add a block is the race in Bitcoin mining. The computer that adds it is paid new bitcoin plus the transaction fees in the batch. A Bitcoin halving cuts only the new bitcoin. One confirmation means the payment is in a block. Wallets often wait for more blocks on top before they treat a large payment as settled, because each extra block makes a rewrite harder.
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Two spans that sit on the ten minutes
210,000 blocks is the halving span. At about ten minutes a block, that span is about four years, and then the new bitcoin in each block is cut in half. 2,016 blocks is the difficulty span. At the same ten-minute target, 2,016 blocks is about two weeks, and that is when mining difficulty can change. Ten minutes is a target the network steers toward, not a clock, so a real stretch of blocks can run a little fast or a little slow.
What a block means when you rent hashrate
You don't build the batch yourself. A pool prepares the work, ASIC miners hash the header, and a block is found when one attempt is accepted. Your rented TH/s, which is your hashrate, is your share of those attempts. A mining pool is how a found block is split. The machines are SHA-256 miners such as the Antminer S21 XP Hyd, the Whatsminer M60, and the Antminer S19 Pro. That kind of hardware is an ASIC miner.
Bitcoin mining and electricity is the watts those attempts draw. Bitcoin mining rewards and payouts is the day that follows a stretch of blocks: bitcoin mined, electricity taken out, and what is left. Hosted hashrate and buying a miner is how you take part by renting the attempts instead of owning a machine.
Frequently asked questions
An 80-byte header and a list of transactions. The header points at the previous block and carries a Merkle root that commits to every transaction in the list.
The target is about ten minutes. Difficulty is what pulls a fast or slow stretch back toward that pace.
The miner that found it, through the coinbase transaction. The pay is new bitcoin plus the fees on the transactions in that block.
The payment is included in one block. Further blocks built on top of that one are further confirmations.
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The latest Bitcoin miners
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