<p>This was discussed in the mailing list a while back:
<a href="http://sourceforge.net/mailarchive/message.php?msg_id=30824341" rel="nofollow">http://sourceforge.net/mailarchive/message.php?msg_id=30824341</a></p>

<p>I'm guessing 32-bit timestamp was used by Satoshi in the original client and the 64-bit timestamp was introduced later to avoid timestamp overflow.</p>

<p>We may need to change (hardfork) the old 32-bit timestamp fields to 64-bit at some point. See <a href="https://en.bitcoin.it/wiki/Hardfork_Wishlist" rel="nofollow">https://en.bitcoin.it/wiki/Hardfork_Wishlist</a></p>

CC BY-SA 3.0
2013-12-29T23:16:04.633Z
2013-12-29T23:16:04.633Z
bitnodes
<p>Reading <a href="https://en.bitcoin.it/wiki/Protocol_specification#Block_Headers" rel="noreferrer"><em>Block Headers</em></a> on the Bitcoin wiki, I learned that the timestamp in a block header is four bytes, and the timestamp in the "version" message is eight bytes. Why are there two sizes, and why isn't it more consistent?</p>

<p><img src="https://i.sstatic.net/42Epo.png" alt="Enter image description here"></p>

CC BY-SA 3.0
2013-12-29T17:33:21.460Z
This is actually a good question.
Steven Roose
<protocol>
Why are there two byte sizes for timestamps in the Bitcoin protocol?
Ning
# Why are there two byte sizes for timestamps in the Bitcoin protocol?

(Asked by: username_0 on 2013-12-29)

Reading [*Block Headers*](https://en.bitcoin.it/wiki/Protocol_specification#Block_Headers) on the Bitcoin wiki, I learned that the timestamp in a block header is four bytes, and the timestamp in the "version" message is eight bytes. Why are there two sizes, and why isn't it more consistent?

![Enter image description here](https://i.sstatic.net/42Epo.png)

**Tags:** protocol

> **Comments:**
> **username_1**: This is actually a good question.  

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## 1 answers

### Answer by username_2 on 2013-12-29. Score: 4 | Accepted answer

This was discussed in the mailing list a while back:
<http://sourceforge.net/mailarchive/message.php?msg_id=30824341>

I'm guessing 32-bit timestamp was used by Satoshi in the original client and the 64-bit timestamp was introduced later to avoid timestamp overflow.

We may need to change (hardfork) the old 32-bit timestamp fields to 64-bit at some point. See <https://en.bitcoin.it/wiki/Hardfork_Wishlist>


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