user1489: Where do I find the total number of bitcoins currently out there?

user80841: 
Fun Fact:

In fact, there are only 21 million Bitcoins that can be mined in total. Once miners have unlocked this many Bitcoins, the planet's supply will essentially be tapped out, unless Bitcoin's protocol is changed to allow for a larger supply.

Where do I find the total number of bitcoins currently out there?

https://bitcoincharts.com is a good place where you can find it.
The number in circulation at the moment is 16.523M

user1489: The number of bitcoins currently in circulation can be found at BlockChain.info or BitcoinCharts.com
Background
The rate at which new bitcoins are mined follows a predefined schedule, with a new block appearing roughly every 10 minutes. The amount of bitcoins in a newly mined block started as 50 and gets halved every 210,000 blocks.
There can be at most 20999999.9769 BTC, so nearly 21 million bitcoins.

user208: If you are running Bitcoin Core, you can see the total amount in circulation using the RPC call gettxoutsetinfo (in the Bitcoin-Qt debug console, or using bitcoin-cli if you run bitcoind).
At the time of writing, the output is: 
{
  "height": 517245,
  ...
  "total_amount": 16965398.58586455
}

which means there are currently ~17 million BTC in circulation. This number takes into account certain types of destroyed coins.
See also this answer of mine about how many there will eventually be.

1489: <p>Where do I find the total number of bitcoins currently out there?</p>
 80841: <blockquote>
  <p>Fun Fact:</p>
</blockquote>

<p>In fact, there are only 21 million Bitcoins that can be mined in total. Once miners have unlocked this many Bitcoins, the planet's supply will essentially be tapped out, unless Bitcoin's protocol is changed to allow for a larger supply.</p>

<blockquote>
  <p>Where do I find the total number of bitcoins currently out there?</p>
</blockquote>

<p><a href="https://bitcoincharts.com" rel="nofollow noreferrer">https://bitcoincharts.com</a> is a good place where you can find it.</p>

<p>The number in circulation at the moment is 16.523M</p>
 1489: <p>The number of bitcoins currently in circulation can be found at <a href="https://blockchain.info/charts/total-bitcoins" rel="nofollow noreferrer">BlockChain.info</a> or <a href="http://bitcoincharts.com/bitcoin/" rel="nofollow noreferrer">BitcoinCharts.com</a></p>
<h2>Background</h2>
<p>The rate at which new bitcoins are mined follows a predefined schedule, with a new block appearing roughly every 10 minutes. The amount of bitcoins in a newly mined block started as 50 and gets halved every 210,000 blocks.</p>
<p>There can be at most <a href="//bitcoin.stackexchange.com/a/9962/1489">20999999.9769 BTC</a>, so nearly 21 million bitcoins.</p>
 208: <p>If you are running Bitcoin Core, you can see the total amount in circulation using the RPC call <code>gettxoutsetinfo</code> (in the Bitcoin-Qt debug console, or using bitcoin-cli if you run bitcoind).</p>

<p>At the time of writing, the output is: <code>
{
  "height": 517245,
  ...
  "total_amount": 16965398.58586455
}
</code></p>

<p>which means there are currently ~17 million BTC in circulation. This number takes into account certain types of destroyed coins.</p>

<p>See also <a href="https://bitcoin.stackexchange.com/questions/38994/will-there-be-21-million-bitcoins-eventually/38998#38998">this answer of mine</a> about how many there will eventually be.</p>
