Monday, November 29

# python – calculate transaction fee

0
15 I have been trying to write an application for transferring bitcoin programmatically using python and bit library. However, I’m currently stuck on how to calculate transaction fee.

``````from bit import Key
from bit import wif_to_key

key = Key('key_is_ommited')
key.get_unspents()

targetwallet="key_is_ommited"
amountasbtc = 0.00007
x = key.send([(targetwallet, amountasbtc, 'btc')], fee=102)
print(x)

``````

I understand that the fee 102 is in satoshi per kb and I need to “guesstimate” how much kb the transaction going to be so I can “guesstimate” how much the fee going to be. when this question was written the transaction is about \$12 in cost.

and also I found out Bit library has a function to measure transaction size with this formula:

``````(42 + 272×(number of inputs) + 128×(number of outputs))/4
``````

is input = 1 (bitcoin wallet address)
and outputs is = 2 (1 destination address and 1 change address)?

so if I’m sending to 5 address that means is about 6 output?