More questions about transaction input and output

[Charles-Tim]

Yesterday, there was a thread about using high fee on decentralized wallets to send low fee. For example, using 0.003 btc to send 0.0001 btc, this has never happened to me before but I realized from the thread it could happen.

The link to the thread
https://bitcointalk.org/index.php?topic=5262685.0

So, there was a great answers from LoyceV and mocacinno which was so helpful and led me to reading this thread below by LoyceV.

https://bitcointalk.org/index.php?topic=2848987.0

I understand the thread but I have a question to ask

I know using one address is not recommendable but just for the sake of knowing, if using one address for the many input with few or far less output, can it still lead to increase transactions fee?

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[ranochigo]

I know using one address is not recommendable but just for the sake of knowing, if using one address for the many input with few or far less output, can it still lead to increase transactions fee?

Yes. Transactions consists of scripts and the outputs defines the requirements needed to spend the UTXOs. For each transaction, there is a script that fulfills the requirement to spend the UTXOs (inputs).

That being said, within a transaction, for each UTXO, the script will define the public key and signature for each and every input. This means that it doesn't matter if you're spending from different addresses because the size of each individual inputs will be the same. The only thing that affects the size is the type of transaction and the number of inputs and outputs.

[Charles-Tim]

Consolidate small inputs
If you have many small inputs, now is the perfect time to consolidate them into one new input! If you're not in a hurry to get a confirmation, you can set a very low fee and just wait. Once it's confirmed, your funds can be send in a much smaller transaction, which means you'll safe a lot on fees if you want to make a transaction when fees are high again. If you have enough small inputs, you can safe up to 95% or more on fees!

@ranochigo, I am still learning and getting to know more about bitcoin. I was just confused about what LoyceV posted, and I want to know more about it. I will be so thankful if anyone can recommend me a book I can read to fully understand this.

[ranochigo]

@ranochigo, I am still learning and getting to know more about bitcoin. I was just confused about what LoyceV posted, and I want to know more about it. I will be so thankful if anyone can recommend me a book I can read to fully understand this.

https://github.com/bitcoinbook/bitcoinbook/

Consolidating inputs means that you're taking many UTXOs (eg. 10 x 0.01BTC) to spend and convert to a single UTXO in the output (1 X 0.1BTC). Taking into account what I said, spending one UTXO can save you a lot of space as the transaction would only have 1 set of signature and public key as opposed to having spend 10 sets of signatures.

When you consolidate them at a low fee, you don't have to spend a lot more when the fees are higher.

[bitmover]

I know using one address is not recommendable but just for the sake of knowing, if using one address for the many input with few or far less output, can it still lead to increase transactions fee?

It doesn't make any difference in terms of fees if you have 10 inputs in 1 or 10 addresses. THe number of inputs is what matters.

You shouldn't use the same address just for privacy reasons. It does not affect fees.

Mastering Bitcoin, as mentioned already, is an amazing book. You can watch some very good videos from the author in his youtube channel, take a look :
https://www.youtube.com/channel/UCJWCJCWOxBYSi5DhCieLOLQ

[Charles-Tim]

I can now understand very well, regardless of using same address or not, what matters is the transaction input itself. And for privacy reasons, using only one address is not recommendable. I appreciate all your answers.