user67288: I'm sure this a basic question, but I would like to check my understanding. 
At the moment, a miner who grows the blockchain by confirming a block is rewarded with 12.5 bitcoins. This incentivises miners to validate transactions. 
Today each bitcoin is worth $13032.00.
It is really correct that if Bob sends Alice some tiny fraction, say one ten-thousandth, of a bitcoin, today worth $1.30, then each confirmation is worth $162,900.00 to the miner?
If this is correct, then it is only economical to offer a transaction fee comparable in value to the miner's reward when the transaction is huge. So as a follow up, I would like to ask:
What are typical transaction fees at the moment, and how is this likely to change as the number of bitcoins approaches its theoretical maximum of 21 million?

user47883: Block reward and fees are not really related. A miner will get the basic reward of 12.5 bitcoin no matter what. But the miner also has some space available in the block that they can fill with transactions. This does not incur any cost on the miner. So as long as there is space in the block the miner can either mine the block without Bobs tx for a reward of 12.5 btc, or the miner can include Bobs tx, which propbaly pays very little fee, for a reward of 12.500001 btc. A rational miner will always choose 12.500001 over just 12.5 even if the difference is really small. Fees increase if there are more tx than can fit into a single block. In that case a rational miner will pick the tx with the highest fees and not include the tx with very low fee.

user49662: The reward is for a block, and a typical block generally contains around 2,500 separate transactions in it.
Typical transaction fees seem to be around $8 (USD), so transaction fees in a block are typically around $20,000.
The miner who successfully submits a block receives:
   $162,500 (12.5 BTC * $13,000) : reward
 +  $20,000 (2,500 tx * $8 ea.)  : tx fees
--------------------------------
   $182,500 (approximately)


67288: <p>I'm sure this a basic question, but I would like to check my understanding. </p>

<p>At the moment, a miner who grows the blockchain by confirming a block is rewarded with 12.5 bitcoins. This incentivises miners to validate transactions. </p>

<p>Today each bitcoin is worth $13032.00.</p>

<p>It is really correct that if Bob sends Alice some tiny fraction, say one ten-thousandth, of a bitcoin, today worth $1.30, then each confirmation is worth $162,900.00 to the miner?</p>

<p>If this is correct, then it is only economical to offer a transaction fee comparable in value to the miner's reward when the transaction is huge. So as a follow up, I would like to ask:</p>

<p>What are typical transaction fees at the moment, and how is this likely to change as the number of bitcoins approaches its theoretical maximum of 21 million?</p>
 47883: <p>Block reward and fees are not really related. A miner will get the basic reward of 12.5 bitcoin no matter what. But the miner also has some space available in the block that they can fill with transactions. This does not incur any cost on the miner. So as long as there is space in the block the miner can either mine the block without Bobs tx for a reward of 12.5 btc, or the miner can include Bobs tx, which propbaly pays very little fee, for a reward of 12.500001 btc. A rational miner will always choose 12.500001 over just 12.5 even if the difference is really small. Fees increase if there are more tx than can fit into a single block. In that case a rational miner will pick the tx with the highest fees and not include the tx with very low fee.</p>
 49662: <p>The reward is for a <em>block</em>, and a typical block generally contains around 2,500 separate transactions in it.</p>

<p>Typical transaction fees seem to be around $8 (USD), so transaction fees in a block are typically around $20,000.</p>

<p>The miner who successfully submits a block receives:</p>

<pre><code>   $162,500 (12.5 BTC * $13,000) : reward
 +  $20,000 (2,500 tx * $8 ea.)  : tx fees
--------------------------------
   $182,500 (approximately)
</code></pre>
