<p>There is a protocol rule which prohibits generated BTC from being spent until it has 100 confirmations. The Satoshi client has an additional safety margin: it won't let you spend generated BTC until it has 120 confirmations. The purpose of this rule is to prevent long chain splits from invalidating lots of transactions that spend newly-generated BTC. For example, this rule prevented non-coinbase transactions from being invalidated after the <a href="https://en.bitcoin.it/wiki/Incidents#Value_overflow">overflow incident</a> invalidated 50+ blocks.</p>

<p>Some pools (e.g. Eligius) pay people by putting the payments <em>in</em> generation transactions. The recipients still won't be able to spend this BTC for 100 blocks, but at least the payments will appear in their Bitcoin clients right away.</p>

CC BY-SA 3.0
2012-04-21T21:35:48.243Z
2012-04-21T21:35:48.243Z
theymos
<p>According to <a href="https://bitcoin.stackexchange.com/questions/1170/why-is-6-the-number-of-confirms-that-is-considered-secure">this question here</a>, 6 confirmations can be considered 'secure enough'. Some pools out there also offer payout at 100 confirms but that's still substantially higher than 6.</p>

<p>Why is such a high confirmation count required for this?</p>

<mining-pools><immature-coins>
Why do mining pools require 120 confirms for a solved block before payout?
greatwolf
# Why do mining pools require 120 confirms for a solved block before payout?

(Asked by: username_0 on 2012-04-21)

According to [this question here](https://bitcoin.stackexchange.com/questions/1170/why-is-6-the-number-of-confirms-that-is-considered-secure), 6 confirmations can be considered 'secure enough'. Some pools out there also offer payout at 100 confirms but that's still substantially higher than 6.

Why is such a high confirmation count required for this?

**Tags:** mining-pools, immature-coins


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## 1 answers

### Answer by username_1 on 2012-04-21. Score: 12 | Accepted answer

There is a protocol rule which prohibits generated BTC from being spent until it has 100 confirmations. The Satoshi client has an additional safety margin: it won't let you spend generated BTC until it has 120 confirmations. The purpose of this rule is to prevent long chain splits from invalidating lots of transactions that spend newly-generated BTC. For example, this rule prevented non-coinbase transactions from being invalidated after the [overflow incident](https://en.bitcoin.it/wiki/Incidents#Value_overflow) invalidated 50+ blocks.

Some pools (e.g. Eligius) pay people by putting the payments *in* generation transactions. The recipients still won't be able to spend this BTC for 100 blocks, but at least the payments will appear in their Bitcoin clients right away.


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