user20967: According to the Blockchain.info: Cost per Transaction, the latest "Cost per Transaction" value is 16 USD. Apparently, it's not the transaction fee, what does it mean then?

user5406: On the chart overview page you find the description "Cost per Transaction: A chart showing miners revenue divided by the number of transactions.".
Meaning, it's the total value of the block reward of a block divided by the number of transactions confirmed on the network in that block.

Here is an example with made up numbers:

Block reward is 25 BTC + 0.1 BTC in transaction fees. 
There are 502 transactions in the block.
Current exchange rate is 367.3 USD/BTC.

25.1 BTC / 502 transactions = 0.05 BTC per transaction
367.30 USD/BTC * 0.05 BTC per transaction = $18.37 per transaction

Concerning what will happen after the regular block reward is reduced/discontinued, check out:

Will Bitcoin suffer from a mining Tragedy of the Commons when mining fees drop to zero?
How much will transaction fees eventually be?
What happens once the mining reward gets cut in half?


20967: <p>According to the <a href="https://blockchain.info/charts/cost-per-transaction" rel="nofollow">Blockchain.info: Cost per Transaction</a>, the latest "Cost per Transaction" value is 16 USD. Apparently, it's not the transaction fee, what does it mean then?</p>
 5406: <p>On the <a href="https://blockchain.info/charts" rel="nofollow noreferrer">chart overview page</a> you find the description <strong>"Cost per Transaction: A chart showing miners revenue divided by the number of transactions."</strong>.</p>

<p>Meaning, it's the <strong>total</strong> value of the block reward of a block <em>divided</em> by the number of transactions confirmed on the network in that block.</p>

<hr>

<p><strong>Here is an example with made up numbers:</strong></p>

<ul>
<li>Block reward is <code>25 BTC + 0.1 BTC</code> in transaction fees. </li>
<li>There are <code>502</code> transactions in the block.</li>
<li>Current exchange rate is <code>367.3 USD/BTC</code>.</li>
</ul>

<p><code>25.1 BTC / 502 transactions = 0.05 BTC per transaction</code></p>

<p><code>367.30 USD/BTC * 0.05 BTC per transaction = $18.37 per transaction</code></p>

<hr>

<p>Concerning what will happen after the regular block reward is reduced/discontinued, check out:</p>

<ul>
<li><a href="https://bitcoin.stackexchange.com/q/3111/5406">Will Bitcoin suffer from a mining Tragedy of the Commons when mining fees drop to zero?</a></li>
<li><a href="https://bitcoin.stackexchange.com/q/876/5406">How much will transaction fees eventually be?</a></li>
<li><a href="https://bitcoin.stackexchange.com/q/4796/5406">What happens once the mining reward gets cut in half?</a></li>
</ul>
