<blockquote>
<p>in picture-1 transactions are out of block and in picture-2 transactions are included in block</p>
</blockquote>
<p>In your picture-1, the transactions are <strong>NOT</strong> shown as outside the block. They are shown as outside the <em>&quot;block header&quot;</em></p>
<p>Your picture-1 has the caption &quot;Simplified Bitcoin Block Chain&quot;. You should take care not to interpret a simplified diagram as if it were completely accurate. The second diagram is also simplified and not a complete specification of data in a block.</p>
<p>Both these diagrams have misleading elements. For example the direction of arrows in the first diagram. The inclusion of &quot;proof of work&quot; in the second diagram as if that were a data item stored in the block structure. It isn't.</p>
<hr />
<blockquote>
<p>Are transactions included in a block or is only the Merkle-root hash included in a block</p>
</blockquote>
<p>The cause of this confusion is that</p>
<ul>
<li>The block hash includes the block header only†.</li>
<li>The block data includes a block-header and <em>all</em> transaction data.</li>
</ul>
<p>†The hash of the block does not <em>directly</em> include the transaction data. The transaction data is included <em>indirectly</em>.</p>
<p>One of the items in the block header is the Merkle root. The Merkle root is a hash resulting from repeated pairwise hashing of transaction data. A consequence of this is that altering any transaction <em>would</em> result in a different block hash.</p>
<hr />
<p>See</p>
<ul>
<li><a href="https://en.bitcoin.it/wiki/Protocol_documentation#block" rel="nofollow noreferrer">Block structure</a></li>
<li><a href="https://en.bitcoin.it/wiki/Protocol_documentation#tx" rel="nofollow noreferrer">Transaction structure</a></li>
<li><a href="https://bitcoin.stackexchange.com/q/114108/13866">What are the components of the raw block shown in this image?</a></li>
<li><a href="https://bitcoin.stackexchange.com/q/113631/13866">In what format does a block store the transaction data?</a></li>
</ul>

CC BY-SA 4.0
2022-07-17T12:30:18.020Z
I believe the field "proof of work" referred to is actually the nonce; that is sometimes referred to as the proof.
Pieter Wuille
CC BY-SA 4.0
2022-07-17T21:07:57.467Z
@Pieter: In Picture-2, "proof of work" is pointed to by "previous block" in the next block and it starts with many zeroes. Aren't both rather suggestive of block hash?
RedGrittyBrick
CC BY-SA 4.0
2022-07-17T22:24:12.613Z
Oh, yes, I guess that's an attempt at referring to the block hash. Strange that it's not hexadecimal though.
Pieter Wuille
CC BY-SA 4.0
2022-07-11T09:33:33.350Z
2022-07-11T10:07:33.597Z
2022-07-11T10:07:33.597Z
RedGrittyBrick
<p>Merkle tree root exists and is stored inside <strong>Block header</strong>.</p>
<p>Transactions are themselves the leafs of the merkle tree.</p>
<p>The merkle tree is used to attach Transactions to the <strong>Block header</strong>.</p>
<p>Therefore, in Bitcoin, <strong>Block</strong> is <strong>Block header</strong> and <strong>Transactions</strong></p>

CC BY-SA 4.0
2022-07-11T17:16:57.467Z
2022-07-11T17:16:57.467Z
Hugo Franklin
<p>Before broadcasting block into bitcoin blockchain, Does a Block transactions are included in a block or only the hash of them are included in a block. While I am surfing through net, I came across two images which are very ambiguity because in picture-1 transactions are out of block and in picture-2 transactions are included in block and the images are as shown below:</p>
<p><strong>Picture -1:</strong>
<a href="https://i.sstatic.net/KP2ed.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/KP2ed.png" alt="1" /></a></p>
<p><strong>Picture -2</strong></p>
<p><a href="https://i.sstatic.net/oHxys.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/oHxys.png" alt="2" /></a></p>

<transactions><blockchain><block>
Are transactions included in a block or is only the Merkle-root hash included in a block
Arjun Reddy
# Are transactions included in a block or is only the Merkle-root hash included in a block

(Asked by: username_0 on 2022-07-11)

Before broadcasting block into bitcoin blockchain, Does a Block transactions are included in a block or only the hash of them are included in a block. While I am surfing through net, I came across two images which are very ambiguity because in picture-1 transactions are out of block and in picture-2 transactions are included in block and the images are as shown below:

**Picture -1:**
[![1](https://i.sstatic.net/KP2ed.png)](https://i.sstatic.net/KP2ed.png)

**Picture -2**

[![2](https://i.sstatic.net/oHxys.png)](https://i.sstatic.net/oHxys.png)

**Tags:** transactions, blockchain, block


---

## 2 answers

### Answer by username_1 on 2022-07-11. Score: 2

> in picture-1 transactions are out of block and in picture-2 transactions are included in block

In your picture-1, the transactions are **NOT** shown as outside the block. They are shown as outside the *"block header"*

Your picture-1 has the caption "Simplified Bitcoin Block Chain". You should take care not to interpret a simplified diagram as if it were completely accurate. The second diagram is also simplified and not a complete specification of data in a block.

Both these diagrams have misleading elements. For example the direction of arrows in the first diagram. The inclusion of "proof of work" in the second diagram as if that were a data item stored in the block structure. It isn't.

---

> Are transactions included in a block or is only the Merkle-root hash included in a block

The cause of this confusion is that

* The block hash includes the block header only†.
* The block data includes a block-header and *all* transaction data.

†The hash of the block does not *directly* include the transaction data. The transaction data is included *indirectly*.

One of the items in the block header is the Merkle root. The Merkle root is a hash resulting from repeated pairwise hashing of transaction data. A consequence of this is that altering any transaction *would* result in a different block hash.

---

See

* [Block structure](https://en.bitcoin.it/wiki/Protocol_documentation#block)
* [Transaction structure](https://en.bitcoin.it/wiki/Protocol_documentation#tx)
* [What are the components of the raw block shown in this image?](https://bitcoin.stackexchange.com/q/114108/13866)
* [In what format does a block store the transaction data?](https://bitcoin.stackexchange.com/q/113631/13866)

> **Comments:**
> **username_2**: I believe the field "proof of work" referred to is actually the nonce; that is sometimes referred to as the proof.  
> **username_1**: @username_2: In Picture-2, "proof of work" is pointed to by "previous block" in the next block and it starts with many zeroes. Aren't both rather suggestive of block hash?  
> **username_2**: Oh, yes, I guess that's an attempt at referring to the block hash. Strange that it's not hexadecimal though.  

---

### Answer by username_3 on 2022-07-11. Score: 1

Merkle tree root exists and is stored inside **Block header**.

Transactions are themselves the leafs of the merkle tree.

The merkle tree is used to attach Transactions to the **Block header**.

Therefore, in Bitcoin, **Block** is **Block header** and **Transactions**


---

