How many bytes does a P2PKH input have? I'm finding a few different numbers:
- Why does the default miner implementation use pay-to-pubkey? states:
push + sig + push + key = 1 + 72 + 1 + 61 = 139
- Princeton Bitcoin Book states [p.123]:
The approximate size of a transaction is 148 bytes for each input[…]
- A knowledgeable Bitcoin developer calculated from the top of the mind for me over coffee:
PREVOUT + SCRIPTSIG = 36 + (1 + 1 + 33 + 1 + (71 or 72)) = 143 or 144
I couldn't find further information in the Bitcoin Developer Guide or the wiki.
Bonus-question: How come there are different numbers? Did the size change over time?