# What is a block?

A Bitcoin block is a batch of transactions plus an 80-byte header that links it to the chain and proves the work done. See what is inside one.

Canonical page: https://mybitcoinexplorer.com/learn/what-is-a-block
Topic: Blocks and the blockchain
Published: 2026-10-29
Updated: 2026-10-30


## Two parts
> Diagram: A block: an 80-byte header followed by its transactions — 
- The **[header](https://mybitcoinexplorer.com/learn/block-header)**: 80 bytes of summary information, including the previous block's hash and the proof of work.
- The **transactions**: starting with the miner's [The coinbase transaction](https://mybitcoinexplorer.com/learn/coinbase-transaction), followed by up to a few thousand others.

## How often?
On average one block every 10 minutes. The network adjusts [difficulty](https://mybitcoinexplorer.com/learn/difficulty-adjustment) every 2,016 blocks to keep it that way. That's about 144 blocks per day.

## How big?
Blocks are limited by **weight**: at most 4,000,000 weight units, which in practice means up to about 1.5 to 2.5 MB depending on the transactions. See [Block size and the weight limit](https://mybitcoinexplorer.com/learn/block-size-and-weight-limit).

## Each block has
| Property | Example |
|---|---|
| Height | its position in the chain, see [Block height](https://mybitcoinexplorer.com/learn/block-height) |
| Hash | the double SHA-256 of its header |
| Time | set by the miner, see [Block timestamps](https://mybitcoinexplorer.com/learn/block-timestamps) |
| Transaction count | from 1 to several thousand |

Browse real ones in our [explorer](/blocks).


## Inside a real block
Open the [latest block](/blocks) on MyBitcoinExplorer. You'll find its height and hash, how many transactions it holds, its size and weight, the timestamp, and the full list of transactions starting with the coinbase. Click any transaction to see its inputs, outputs and fee.

## Why blocks and not single transactions?
Grouping transactions lets the network agree on order in batches. Proof of work is spent once per block instead of once per payment, and nodes check ordering at a manageable pace: about 144 blocks per day.


## Key takeaways

- A block is an 80-byte header plus a list of transactions.
- The coinbase transaction always comes first.
- Blocks arrive about every 10 minutes and are limited by weight.

## Common questions

### Can a block be empty?

Yes. A block can contain only the coinbase transaction. Miners sometimes mine those right after a new block, before they have selected transactions.

### Who decides what goes in a block?

The miner who builds it, within the consensus rules.

### How many transactions are in a Bitcoin block?

Typically between about 2,000 and 7,000, depending on how big the transactions are.

### How often is a block mined?

About every 10 minutes on average, though individual gaps vary a lot.

## Related lessons

- [The block header](https://mybitcoinexplorer.com/learn/block-header)
- [What is the blockchain?](https://mybitcoinexplorer.com/learn/what-is-the-blockchain)
- [Block size and the weight limit](https://mybitcoinexplorer.com/learn/block-size-and-weight-limit)
- [The coinbase transaction](https://mybitcoinexplorer.com/learn/coinbase-transaction)