How compute transaction fee?

[Frodek]

We have sample transaction: https://blockchain.info/tx/fa67048a1d19de38779d9a784980f1fbbc2cffac51e9cf2eb5428cf50463e173
Output is 0.2867 BTC + 0.00057499 BTC = 0.28727499 BTC
Fee is difference between Total Input = 0.28747499 BTC and Total Output = 0.28727499 BTC.
How get value of Total Input?

[achow101]

How get value of Total Input?

You get the values of the outputs that the inputs reference.

[Frodek]

I must analyze whole blockchain and hundred of millions addresses?

[achow101]

I must analyze whole blockchain and hundred of millions addresses?

No, just the output each input references. The inputs specify a transaction id and the output index that the input spends from.

[marcuslong]

We have sample transaction: https://blockchain.info/tx/fa67048a1d19de38779d9a784980f1fbbc2cffac51e9cf2eb5428cf50463e173
Output is 0.2867 BTC + 0.00057499 BTC = 0.28727499 BTC
Fee is difference between Total Input = 0.28747499 BTC and Total Output = 0.28727499 BTC.
How get value of Total Input?

Nice question hmm i need to research it but i think they dont base it in the output in input because other transaction fees that i see is too much fees.
But i think its error in the blockchain i need to know to too so that when im using blockchain i know why it cost to much fee

[piotr_n]

I must analyze whole blockchain and hundred of millions addresses?

kind of. you must keep a list of all "unspent outputs" - it's usually called UTXO database.

alternatively you can download the raw translations (that the input refers to) from one of the block explorers.
it's actually secured - you just need to verify the downloaded transaction against the ID that is being spent.