Estimated BTC Transacted - What is this

[raymonddaf]

Hi I am new to BTC, I have a query on the Estimated BTC Transacted, can someone explain what this is? 

My transaction is defe548b8af9098953053d8107c7763ede3b379144306642014b999745b8c0a4

I am just trying to make sense of it, below is my transfer from the exchange, why does the Blockchain transaction say 0.390023 BTC When the exchange differs:

Credited
+ ฿ 0.36701145 BTC
Market rate  (£ 1,350.30 GBP)
+ ฿ 0.37028862 BTC
Exchange fee  (0.75 %)
- ฿ 0.00277717 BTC
Network fee
- ฿ 0.0005 BTC

[mocacinno]

Hi I am new to BTC, I have a query on the Estimated BTC Transacted, can someone explain what this is?  

My transaction is defe548b8af9098953053d8107c7763ede3b379144306642014b999745b8c0a4

I am just trying to make sense of it, below is my transfer from the exchange, why does the Blockchain transaction say 0.390023 BTC When the exchange differs:

Credited
+ ฿ 0.36701145 BTC
Market rate  (£ 1,350.30 GBP)
+ ฿ 0.37028862 BTC
Exchange fee  (0.75 %)
- ฿ 0.00277717 BTC
Network fee
- ฿ 0.0005 BTC

When the exchange creates a transaction, he uses an unspent output that can be spend by one of their exchange addresses as an input to generate your withdrawal transaction.

Your withdrawal transaction uses this input to generate two outputs: one that can be spent by you, and one that can be spent by one of their change addresses.

A miner needs to include this withdrawal transaction into the block he/she is currently working on. To make it worth their wile, you have to pay a miners fee. The higher the miner's fee, the better the chance he'll add your transaction to a block.

The difference between (sum of inputs) and (sum of outputs) = fee.

BTW: the fee is calculated based on the size of the transaction, the size depends on the number of inputs and outputs (just for your future reference).

In your case, https://blockchain.info/tx/defe548b8af9098953053d8107c7763ede3b379144306642014b999745b8c0a4 said following:

Input = 0.390023 that can be spent by C91S6871QRTTTMdhVsQEv9LbdU684eamg (an exchange address)
Output 1 = 0.36701145 that can be spent by 1BK8SiGnb51ZNcGoUgLQqEnsxVvYrsDJpU (blockchain thinks this is the exchange's change address)
Output 2 = 0.02251155 that can be spent by 1C1crrhX2A3QeS4P7QMExRayVUr4c9Asej (blockchain thinks this is your address)

0.390023 - (0.36701145 + 0.02251155) = 0.0005 (this is the miner's fee)

The size of your transaction with 1 input and 2 outputs is 225 bytes. This makes the fee 50000 satoshi's/255 bytes =~ 200 sat/byte

Here's an image out of the bitcoin.org developer guide that will show the basis of transactions graphically (it can get a lot more complex than this tough):

source: https://bitcoin.org/en/developer-guide#block-chain-overview

[raymonddaf]

Thanks for the reply - I understand the miners fee but dont get what the Estimated BTC Transacted   0.02251155 BTC comes in.

I exchanged £500 at Market rate  (£ 1,350.30 GBP) =  ฿ 0.37028862 BTC
Less Exchange fee  (0.75 %- ฿ 0.00277717 BTC) then less Miner Fee - ฿ 0.0005 BTC = ฿ 0.36701145 BTC
All this makes sense

So what is the 0.02251155 is this what the exchange makes, should I just disregard this?

Sorry Newbie trying to learn.

[HCP]

The "estimated BTC transacted" value in blockchain.info explorer, is just their "best guess" at how much BTC was actually sent from PersonA to PersonB, based purely on the output amounts and some weird algorithm that blockinfo has come up with... in a lot of cases, like this one... it is wrong

As mocacinno stated, in that transaction there is 1 input and 2 outputs... and blockchain.info thinks that PersonA (The exchange) sent 0.02251155 BTC to PersonB (You)... and the rest of the input was returned to PersonA's change address. However, based on what you've pasted... you actually got the 0.36701145 BTC...

Now the reason the input to the transaction was 0.390023 BTC when you only wanted 0.37028862 BTC is that this is just the way bitcoins works... you have to spend UTXOs completely... so the exchange just picked a UTXO that was in their wallet that was larger than your request + miner fee and used that to create the transaction, then they got the difference back as change.

Generally speaking, the input amount can (and often does) bear very little resemblance to any amount you are supposed to receive... Especially from organisations dealing in large volumes like exchanges. They could easily have used an input of 10 BTC... you'd still get your 0.36701145 BTC and they'd get their change...

[raymonddaf]

Got it, cheers guys.

[mr108]

Hello,

I came across your post while searching for explanation for a similar transaction here which I don't understand:
https://blockchain.info/tx/9f851991cf75af08689356e2bf8d2fd00f1adf3ebaa224287f013b4f2968947f?show_adv=true

and I still don't understand your case and what "Estimated BTC Transacted" is. But did you at the end receive 0.389523 BTC or did you receive this amount 0.02251155 BTC less?

[HCP]

"Estimated BTC Transacted" is just blockchain.info's "Guess" at how much BTC was actually sent from the sender to the receiver... it really doesn't mean anything and is often wrong.

For instance, the transaction you posted has one input of 4.32064555 BTC and it has two outputs: 0.06005236 BTC and 4.25866271 BTC

Blockchain.info is GUESSING that the 4.25866271 BTC output is "change", so was not being sent to anyone... and that the sender was only sending 0.06005236 BTC to the receiver. So, they put "Estimated BTC Transacted 0.06005236 BTC" as their guess.

You can read about what "change" is, and why it happens here: https://en.bitcoin.it/wiki/Change
If you don't understand why an input of 4.25+ BTC  was used to send 0.06 BTC... read this: https://en.bitcoin.it/wiki/Coin_analogy