user51261: I tried to send 0.001 BTC with Bitcoin-Core, but for some reasons it charged me with a transaction fee of 0.00145271 BTC:
$ bitcoin-cli getinfo|grep balance
"balance": 0.03312022,
$ bitcoin-cli sendtoaddress my_bitcoin_address 0.001
$ bitcoin-cli getinfo|grep balance
"balance": 0.03066751,

Is there any way to know which fee am I going to pay before sending the transaction?

user50934: You can use bitcoin-cli estimatefee to estimate the fees required, and settxfee to set it.  It's usually a bit trickier on the command line, a GUI wallet should show this information before you make the transaction though.

51261: <p>I tried to send 0.001 BTC with Bitcoin-Core, but for some reasons it charged me with a transaction fee of 0.00145271 BTC:</p>

<pre><code>$ bitcoin-cli getinfo|grep balance
"balance": 0.03312022,
$ bitcoin-cli sendtoaddress my_bitcoin_address 0.001
$ bitcoin-cli getinfo|grep balance
"balance": 0.03066751,
</code></pre>

<p>Is there any way to know which fee am I going to pay <strong>before</strong> sending the transaction?</p>
 50934: <p>You can use <code>bitcoin-cli</code> <a href="https://bitcoin.org/en/developer-reference#estimatefee" rel="nofollow noreferrer">estimatefee</a> to estimate the fees required, and <a href="https://bitcoin.org/en/developer-reference#settxfee" rel="nofollow noreferrer">settxfee</a> to set it.  It's usually a bit trickier on the command line, a GUI wallet should show this information before you make the transaction though.</p>
