<p>Let's assume that there are two UTXO under your control, <code>U1</code> and <code>U2</code>.</p>

<p>You use <code>U1</code> and <code>U2</code> to create a transaction <code>T1</code> that would create <code>U3</code> when confirmed. <code>U1</code> and <code>U2</code> therefore are <em>inputs</em> of the unconfirmed transaction <code>T1</code> and <code>U3</code> is an output of <code>T1</code>. </p>

<p><code>U1</code> and <code>U2</code> are unspent, however another transaction <code>T2</code> spending either or both of them would be considered a doublespend by any node that knew about <code>T1</code> before.</p>

<p>Meanwhile, until <code>T1</code> is confirmed, <code>U3</code> is not part of the UTXO pool. Since the transaction is yet unconfirmed, the newly created output doesn't exist yet.</p>

CC BY-SA 3.0
2017-03-20T14:54:20.700Z
2017-03-20T14:54:20.700Z
Murch
<p>The transactions are considered spent from the nodes that already have the transaction in the <code>mempool</code>, that is, if you try to double-spend the transaction, they will reject the new one. However, if the transaction ends up not being included in a block, they will be dropped from the <code>mempool</code> after a certain time. After that, you will be able to create a new transaction that spends the same <code>UTXOs</code>, since from that point on it won't be considered double-spending. </p>

CC BY-SA 3.0
2017-03-16T14:56:47.393Z
Thanks. How much would taht time be? Because I sent a tx with such a low fee that it's taking too much time to get into a block and my last hope is for it to get dropped from the mempool of the nodes.
miguel
CC BY-SA 3.0
2017-03-16T15:41:47.227Z
It could last a while, I don't know exactly how much, honestly. However, if you are in a hurry, you can use the solution from this answer: http://bitcoin.stackexchange.com/questions/51524/i-sent-out-a-payment-over-a-day-ago-and-its-still-not-confirmed/51534#51534
sr_gi
CC BY-SA 3.0
2017-03-16T14:26:19.493Z
2017-03-16T14:26:19.493Z
sr_gi
<p>Well basically that. If a transaction is in the memory pool, that is, it is not yet in a block but nodes and miners know about it and validated it, Can I send another transaction that double-spends the outputs? that is, are the outputs considered unspent?</p>

CC BY-SA 3.0
2017-03-20T14:48:03.763Z
It is not clear to me whether you are suggesting to doublespend the inputs or the outputs of the unconfirmed transaction.
Murch
<transactions><unconfirmed-transactions><utxo>
Are the outputs of an unconfirmed transaction part of the global UTXO pool?
miguel
# Are the outputs of an unconfirmed transaction part of the global UTXO pool?

(Asked by: username_0 on 2017-03-16)

Well basically that. If a transaction is in the memory pool, that is, it is not yet in a block but nodes and miners know about it and validated it, Can I send another transaction that double-spends the outputs? that is, are the outputs considered unspent?

**Tags:** transactions, unconfirmed-transactions, utxo

> **Comments:**
> **username_1**: It is not clear to me whether you are suggesting to doublespend the inputs or the outputs of the unconfirmed transaction.  

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## 2 answers

### Answer by username_1 on 2017-03-20. Score: 1 | Accepted answer

Let's assume that there are two UTXO under your control, `U1` and `U2`.

You use `U1` and `U2` to create a transaction `T1` that would create `U3` when confirmed. `U1` and `U2` therefore are *inputs* of the unconfirmed transaction `T1` and `U3` is an output of `T1`.

`U1` and `U2` are unspent, however another transaction `T2` spending either or both of them would be considered a doublespend by any node that knew about `T1` before.

Meanwhile, until `T1` is confirmed, `U3` is not part of the UTXO pool. Since the transaction is yet unconfirmed, the newly created output doesn't exist yet.


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### Answer by username_2 on 2017-03-16. Score: 2

The transactions are considered spent from the nodes that already have the transaction in the `mempool`, that is, if you try to double-spend the transaction, they will reject the new one. However, if the transaction ends up not being included in a block, they will be dropped from the `mempool` after a certain time. After that, you will be able to create a new transaction that spends the same `UTXOs`, since from that point on it won't be considered double-spending.

> **Comments:**
> **username_0**: Thanks. How much would taht time be? Because I sent a tx with such a low fee that it's taking too much time to get into a block and my last hope is for it to get dropped from the mempool of the nodes.  
> **username_2**: It could last a while, I don't know exactly how much, honestly. However, if you are in a hurry, you can use the solution from this answer: http://bitcoin.stackexchange.com/questions/51524/i-sent-out-a-payment-over-a-day-ago-and-its-still-not-confirmed/51534#51534  

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