# Merkle tree

Source URL: https://help.blockstream.com/education/glossary/merkle-tree
Updated: 2026-05-26T17:22:20.000Z
Letter: M

---

Named after its inventor, [Ralph Merkle](https://ralphmerkle.com/), a Merkle tree, also known as a hash tree, is a data structure that ensures the integrity of data verification in Bitcoin. Its tree-like structure enables [lightweight nodes](https://blog.blockstream.com/education/nodes/what-are-the-types-of-bitcoin-nodes/) to verify transactions without having to download the entire block by encoding all transactions in a block into a single hash, known as the Merkle root, which is then included in the block header.

Below is an example of how a Merkle tree might look for a block with four transactions:

```
        Merkle Root
             |
      _______|_______
     |               |
  Hash 01         Hash 23
     |               |
  ___|___         ___|___
 |       |       |       |
Hash0  Hash1  Hash2  Hash3
 |       |       |       |
Tx0     Tx1     Tx2     Tx3
```

- Tx0, Tx1, Tx2, Tx3: the individual transactions included in a Bitcoin block.
- Hash0, Hash1, Hash2, Hash3: the hashes of the individual transactions.
- Hash 01: the hash of the concatenation of Hash0 and Hash1.
- Hash 23: the hash of the concatenation of Hash2 and Hash3.
- Merkle root: This is the hash of Hash 01 and Hash 23 concatenation embedded into the block header.

If someone wants to verify that a particular transaction is included in a block, they do not have to download every transaction. Instead, they can download the top part of the Merkle tree (the root) along with a Merkle path (the set of hashes needed to reconstruct the Merkle root from a single transaction).

Navigation: Blockstream Help Center > Education > Glossary > Merkle tree

## Related Terms in This Letter
- [Mempool](https://help.blockstream.com/education/glossary/mempool)
- [Merge conflict](https://help.blockstream.com/education/glossary/merge-conflict)
- [Merkle tree](https://help.blockstream.com/education/glossary/merkle-tree) (current)
- [Mining](https://help.blockstream.com/education/glossary/mining)
- [Miniscript](https://help.blockstream.com/education/glossary/miniscript)
- [Mnemonic](https://help.blockstream.com/education/glossary/mnemonic)
- [Multi-part payments (MPP)](https://help.blockstream.com/education/glossary/multi-part-payments-mpp)
- [MuSig2](https://help.blockstream.com/education/glossary/musig2)