<p>Immediately following the human readable part and separator of a bech32 address is the witness version number. For current bech32 addresses, that version number is 0. According to the encoding table <a href="https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki#bech32" rel="nofollow noreferrer">here</a>, the value for a 0 byte is <code>q</code>. Thus addresses will begin with <code>bc1q</code>.</p>

CC BY-SA 3.0
2018-02-26T19:52:40.270Z
2018-02-26T19:52:40.270Z
Ava Chow
<p>There is of corse BIP173, which explains bc1 for better readability. </p>

<p>More interesting is a <a href="https://bitcointalk.org/index.php?topic=2624630.msg26762627#msg26762627" rel="nofollow noreferrer">thread in bitcointalk</a>, where Greg Maxwell explains details. 
Searching the forum here and bitcointalk for bech32 reveals lots of interesting facts :-)</p>

CC BY-SA 3.0
2018-02-26T19:28:06.763Z
2018-02-26T19:28:06.763Z
pebwindkraft
<p><code>q</code> is the Bech32 encoding of the number 0. For a segwit address, as defined in BIP 173, the number immediately following the separator is the witness version. In this case, bc1q, the q means it is a witness v0 address, which is the only type currently used but allows for easy future addition of new versions</p>

CC BY-SA 3.0
2018-02-26T19:51:47.420Z
2018-02-26T19:51:47.420Z
meshcollider
<p>I understand that it starts bc1.</p>

<p>But 'q' is not what I understand. Can someone explain to me?</p>

<bech32-address>
Why bech32 address always starts with bc1q?
bitcoinlearner
# Why bech32 address always starts with bc1q?

(Asked by: username_0 on 2018-02-26)

I understand that it starts bc1.

But 'q' is not what I understand. Can someone explain to me?

**Tags:** bech32-address


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## 3 answers

### Answer by username_3 on 2018-02-26. Score: 10 | Accepted answer

`q` is the Bech32 encoding of the number 0. For a segwit address, as defined in BIP 173, the number immediately following the separator is the witness version. In this case, bc1q, the q means it is a witness v0 address, which is the only type currently used but allows for easy future addition of new versions


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### Answer by username_1 on 2018-02-26. Score: 4

Immediately following the human readable part and separator of a bech32 address is the witness version number. For current bech32 addresses, that version number is 0. According to the encoding table [here](https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki#bech32), the value for a 0 byte is `q`. Thus addresses will begin with `bc1q`.


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### Answer by username_2 on 2018-02-26. Score: 3

There is of corse BIP173, which explains bc1 for better readability.

More interesting is a [thread in bitcointalk](https://bitcointalk.org/index.php?topic=2624630.msg26762627#msg26762627), where Greg Maxwell explains details.
Searching the forum here and bitcointalk for bech32 reveals lots of interesting facts :-)


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