# Gavin Andresen
# 2011-02-10 22:55:36
# https://bitcointalk.org/index.php?topic=3332.msg46857#msg46857

I figure each bitcoin transaction is currently costing about $US 0.0003 (three-hundredths of a cent) @p{par}

Here's the back-of-the-envelope calculation I used to get to that number: @p{par}

Transaction size:  ~300 bytes. @p{brk}
Disk space cost:  0.05 $US per gigabyte (about $100 for a 2TB hard drive these days) @p{brk}
Bandwidth cost: 0.02 $US per gigabyte @p{brk}
CPU cost:  0  (bad assumption@p{--} anybody want to try to come up with a better estimate?) @p{par}

Size of bitcoin network:  ~10,000 nodes @p{par}

Each transaction is currently sent across the network twice (once on its own, and once when it becomes part of a block).  It is stored on disk once.  So disk+bandwidth cost for one machine is: @p{brk}
 (0.05+0.02+0.02)*(300/1000000000) @p{brk}
... times 10,000 nodes gives $0.00027 per transaction. @p{par}

 @p{brk}
Please check my work@p{--} I usually screw up and add or drop an extra zero when doing these types of calculations. @p{par}