user20886: From the Bitcoin wiki page on transaction fees:

Transaction priority is calculated as a value-weighted sum of input
  age, divided by transaction size in bytes:
priority = sum(input_value_in_base_units * input_age)/size_in_bytes
  Transactions need to have a priority above 57,600,000 to avoid the
  enforced limit

Can somebody clarify what input_value_in_base_units or input_age is?

user2306: input_value_in_base_units is the number of satoshis that the input is worth. One Bitcoin is worth 100,000,000 satoshis.
input_age is how many blocks the input has been present for. An unconfirmed transaction has an age of 0, and one that has 100 confirmations has an age of 100.

20886: <p>From the Bitcoin wiki <a href="https://en.bitcoin.it/wiki/Transaction_fees#Technical_info">page on transaction fees</a>:</p>

<blockquote>
  <p>Transaction priority is calculated as a value-weighted sum of input
  age, divided by transaction size in bytes:</p>
  
  <p>priority = sum(input_value_in_base_units * input_age)/size_in_bytes
  Transactions need to have a priority above 57,600,000 to avoid the
  enforced limit</p>
</blockquote>

<p>Can somebody clarify what input_value_in_base_units or input_age is?</p>
 2306: <p><code>input_value_in_base_units</code> is the number of satoshis that the input is worth. One Bitcoin is worth 100,000,000 satoshis.</p>

<p><code>input_age</code> is how many blocks the input has been present for. An unconfirmed transaction has an age of 0, and one that has 100 confirmations has an age of 100.</p>
