<p>Yes. The transaction ID is SHA256(SHA256(transaction)) as described <a href="https://bitcoin.stackexchange.com/questions/2177/how-to-calculate-a-hash-of-a-tx">here</a> and thus always has a length of 256 bits (32 bytes).</p>

CC BY-SA 3.0
2014-12-18T18:02:15.747Z
2014-12-18T18:02:15.747Z
2017-04-13T12:47:34.187Z
Chuck Batson
<p>Do all bitcoin transaction ids (hashes) have the same length? </p>

<p>I guess it's defined somewhere here: <a href="https://en.bitcoin.it/wiki/Protocol_specification" rel="nofollow">https://en.bitcoin.it/wiki/Protocol_specification</a> but still I couldn't find it.</p>

<protocol><transaction-id><specification>
Are transaction ids always the same length?
Doug Peters
# Are transaction ids always the same length?

(Asked by: username_0 on 2014-12-18)

Do all bitcoin transaction ids (hashes) have the same length?

I guess it's defined somewhere here: <https://en.bitcoin.it/wiki/Protocol_specification> but still I couldn't find it.

**Tags:** protocol, transaction-id, specification


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## 1 answers

### Answer by username_1 on 2014-12-18. Score: 6 | Accepted answer

Yes. The transaction ID is SHA256(SHA256(transaction)) as described [here](https://bitcoin.stackexchange.com/questions/2177/how-to-calculate-a-hash-of-a-tx) and thus always has a length of 256 bits (32 bytes).


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