Raw Transaction Tax

[madmadmax]

How do you calculate it? I have searched google and on this forum and haven't found a single answer.

Are there any low level functions I'm missing?

[CIYAM]

Tax?

Are you trying to work out a tx *fee* amount?

[madmadmax]

Tax?

Are you trying to work out a tx *fee* amount?

Yes haha the bitcoin network "tax" for processing your payment. The tx fee, I know it is charged by kb apparently but how do you get the proper kb for a transaction before you even create it?

[CIYAM]

Okay - refer to this: https://en.bitcoin.it/wiki/Transaction_fees

Just create it the raw tx (with no fee) but don't send it and check its size (and the age of UTXOs if necessary) - remember that paying the fee is simply reducing one of the outputs (generally the change one) by the appropriate amount.

[DannyHamilton]

how do you get the proper kb for a transaction before you even create it?

As CIYAM has pointed out, you don't.  First you create the transaction, then you calculate the fee.