<p>You would create a transaction with two outputs, one being 0.001 BTC to the recipient, another being 24.9989 back to another key you own yourself (called a change output), and the difference of 0.0001 BTC would be fee.</p>

CC BY-SA 3.0
2016-11-05T07:06:24.363Z
So if I don't have an extra address and forget to create output, then I would lose the fund forever correct?
Yangrui
CC BY-SA 3.0
2016-11-05T07:07:30.573Z
Yes, if you forget to add a change output, it will become fee. Bitcoin Core will actually refuse to send transactions that pay too much fee, to protect against this.
Pieter Wuille
CC BY-SA 3.0
2016-11-05T06:16:46.660Z
2016-11-05T06:16:46.660Z
Pieter Wuille
<p>I'm confused by how exactly Bitcoin transaction are calculated. A transaction contains inputs and outputs, and if its inputs exceed its outputs the difference is deemed as the transaction fee. </p>

<p>So, if I just mined a block and received 25 coins in reward, there were no previous transactions related with my address and I want to make a transfer of 0.001 Btc using my 25 Btc balance. Then, there will be a 25 Btc input and a 0.001 Btc output, and the difference in the amount of 24.999 Btc all goes to miners?! Please help me understand.</p>

CC BY-SA 3.0
2016-11-05T08:46:28.853Z
related: [How does change work in a bitcoin transaction?](http://bitcoin.stackexchange.com/q/736/5406)
Murch
<transactions><transaction-fees><change>
How can I use a large input if the difference of the outputs and the inputs goes to the fee?
Yangrui
# How can I use a large input if the difference of the outputs and the inputs goes to the fee?

(Asked by: username_0 on 2016-11-05)

I'm confused by how exactly Bitcoin transaction are calculated. A transaction contains inputs and outputs, and if its inputs exceed its outputs the difference is deemed as the transaction fee.

So, if I just mined a block and received 25 coins in reward, there were no previous transactions related with my address and I want to make a transfer of 0.001 Btc using my 25 Btc balance. Then, there will be a 25 Btc input and a 0.001 Btc output, and the difference in the amount of 24.999 Btc all goes to miners?! Please help me understand.

**Tags:** transactions, transaction-fees, change

> **Comments:**
> **username_1**: related: [How does change work in a bitcoin transaction?](http://bitcoin.stackexchange.com/q/736/5406)  

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## 1 answers

### Answer by username_2 on 2016-11-05. Score: 2 | Accepted answer

You would create a transaction with two outputs, one being 0.001 BTC to the recipient, another being 24.9989 back to another key you own yourself (called a change output), and the difference of 0.0001 BTC would be fee.

> **Comments:**
> **username_0**: So if I don't have an extra address and forget to create output, then I would lose the fund forever correct?  
> **username_2**: Yes, if you forget to add a change output, it will become fee. Bitcoin Core will actually refuse to send transactions that pay too much fee, to protect against this.  

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