Topic: [Edu] Bitcoin Wallet UTXO and Consolidation (Read 268 times)

Thanks Charles and Igebotz for going at each other with healthy and informative replies. I already learnt about how multiple UXTO bumps up the fees during transactions, the examples from Igebotz solidified my understanding even more. I just wanted to say thank you to you both.

I will try out the consolidation feature whenever the network demand is low. Fascinating concepts, I must say.

This thread made me to read materials and I thank Charles-Tim for the material he sent to me for a long time again, I made a review on them and I saw everything in UTXO and from the above quoted statement is the meaning of UTXO. But let meak it clear for those who are still confusing. The bitcoin that was send to you which you have not spent is the UTXO output because it was send to you from another user which is the STXO. The user that spend (Sender) the bitcoin is called Spend Transaction Output. When bitcoin is send, the chunks will detect the blockchain. In the computing system there are always two concepts to know. Input and output. The input is the bitcoin you have and once you see them on your screen it becomes output. And from my first comment, I made mentioned of "change". Now when you are send out bitcoin, you send out to two addresses, one to the recipient address and one to yourself and the one to yourself is called the "change" which leftover for you or the remaining balance which is also known as UTXO. Example, if I am sending 0.004 bitcoin to Charles-Tim out of 0.098 bitcoin the leftover is the change for me which is also unspend Transaction Output (UTXO) and also Charles-Tim too.

For you to understand this better, you can make use of Electrum wallet or Sparrow, they both have testnet. On mobile, you can make use of Bluewallet, but it does not have testnet. Send bitcoin to the same address two times and send bitcoin to another address on the same wallet one time. After doing that:

If you use Sparrow, click on UTXO on Sparrow wallet and you will see what is regarded as UTXO.
If it is Electrum, click on view -> coins, and coin tab will appear which you can click on to show the UTXOs
If you use Bluewallet, click on your wallet in blue -> send -> the three dots menu -> coin control.

Yes, Sparrow is only supporting bitcoin. You can change the unit from sat to BTC if you want. To do that, click on view -> bitcoin unit -> BTC to change it to BTC.

Much more clearer now, so can we transfer the Sats along with a utxo at a time or only UTXO can be transact at a session.


I understand I just want others who don't know the short term to know it too and to be sure of myself too,besides i've never tried sparrow wallet.
I believe also that sparrow  wallet support  only btc since it's in smaller units (sats) .

Great explanation Charles! He dusted everything in a lame man language, that should be helpful and if you have further questions, don't hesitate to ask.


You're right, Sats stands for Satoshi and Sats is the smallest meansure of Bitcoin;

1Sat = 0.00000001 BTC

1Million Sats = 1BTC

I'm not sure any of us has up to 1BTC yet, what we have in our wallets are fraction of Bitcoin (Sats).

The 40,000 Sats in my Op is equal to $10.68 worth of BTC. I didn't want to use the dollar sign as a Bitcoiner.

For illustration:

On wallet 1
Mr. A sent you 1 BTC, that is 1 UTXO
Mr. B sent you 2 BTC, that is UTXO 2
Mr. C sent you 5 BTC, that is UTXO 3 and so on

On wallet 2
On another wallet entirely, let us assume that only Mr. D sent you 8 BTC. That is just 1 UTXO

Let us also assume that you are using the same address type.

The fee that would be required for you to send 1 BTC that Mr. A sent you would be the same amount of fee that will be required for you to send the 8 BTC that Mr. D sent you because the UTXO for both is just one.

If you want to spend UTXO 1 and 2 from wallet 1, the higher the fee will be required. If you want to spend UXTO 1, 2 and 3 on wallet 1, highest fee will be required. The more the UTXO counts required in a transaction, the higher the fee.

I went through it and I should say this is very helpful indeed. However,  the words SATS - I guess it's satoshi and if its not you can correct me but you should have keys to define your short acronyms because of we beginners as we might find it hard to comprehend with all the acronym .

Also, the wallet should be specified at the top as we might loose interest without knowing anything about what we are reading through before getting to the bottom.

Lastly, I don't get the part of transacting UTXO should its it be transferred with a new tranferable Sats or transferred Allthe UTXOs once .
Thanks OP for this.

The term "UTXO" stands for "unspent transactions output". You have unspent transactions output (UTXO) in your wallet for every coin received; not all mobile wallets show you how many UTXO (dust) you have in your wallet, but they are there. The more UTXOs you have, the more fees you must pay to withdraw those coins. Furthermore, some hardware wallets are unable to sign transactions containing an excessive number of UTXOs.

I'm at a loss for words, but I hope this helps.

It is on Electrum wallet. Not on Electrum mobile wallet but on the desktop. On Electrum GUI, click on 'view' -> coins. Coin tab will appear on the GUI, click on it to make use of coin control on Electrum as you will see the lists of UTXOs. You can use it to freeze certain inputs or to spend certain inputs.

On mobile Electrum, you make make use of address freeze instead. Click on the name you named your wallet at the upper left corner -> addresses -> select the address or addresses that you want to freeze and you will freeze address at the lower part of the page it will take you to.

Coin control can be used to freeze not all the UTXOs on an address
But address freeze will freeze all the UTXOs on an address
That is the differences. Which means coin control is better. But if your addresses is having just one UTXO count each, you can make use of address freeze like coin control.

The UTXOs that we are referring to is what you meant as inputs. The UTXOs are the inputs in the transaction you are broadcasting.

Op this term UTXO is not found in the wallet I use so I am not familiar with whole discussion and di way u take explain is not really clear for newbies and non-technical wallet users to participate in the thread. And I don't think the UTXO stuff happens in Electrum wallet because I have not seen such feature in Electrum wallet when I send bitcoin. And this can be discussed by those who use Sparrow wallet and other wallets that has the features. And if it was in Electrum, I would have gotten an idea in it. But from the small knowledge acquire wallet, transaction fee increase base on the input and outputs which Charles-Tim as said. The input which is the sending transaction and the output which has two recipients. One for the destination address and the other return back the send address as changed.  And that also cause di increase of the transaction fee.

DCA savings and signature payment could probably give you that but in my case I was only using it to explain a perfect situation.


No Charles coin control will not work in the scenario I gave, I guess you didn't understand my question and I wasn't asking you to teach me coin control. Zaguru12 gave the perfect answer.

On Sparrow wallet GUI, click on 'UTXO' at the left side, you will see the UTXOs individually. Click on any UTXO that you want to freeze and the image below will appear:



Using this to freeze the UTXOs that you want to freeze.

This is the link:

https://jochen-hoenicke.de/queue/#BTC%20(default%20mempool),24h,weight

I will edit it and include the link in full.

Yes coin control’s sole purpose is for privacy sake but I don’t think there is limitations to its usage. You can freeze just any UTXOs from been spent.

The main point of coin control on this topic is when you have multiple chunks of  little Sats and with the mempool congested resulting into high transaction fees where you don’t feel it is necessary to consolidate your UTXOs at tht time you can freeze some of the this little sats (most of which are change addresses). But with your case of having same number of sats and also having to spend almost all the UTXOs in one transaction then you don’t have any choice but to either consolidate or spend the UTXOs on that transactions (both of which in this case are almost similar in terms of fees to be paid) even if the the transaction fee is high.

Also I don’t see it logical to have left those chunks there with equal sats without consolidating them until when the pool get congested or when you need to use almost all of it, probably because of DCAing?

Coin control is generally used for coin management in order to maintain privacy. Keeping KYCed Bitcoin separate from non-KYCed Bitcoin in your wallet. Allows you to spend any coin you wish, as not everyone wants to spend non-KYCed Bitcoin purchased on DEXs.

If you have 5 Bitcoin chunks (3000 Sats, 3000 Sats, 3000 Sats, 3000 Sats, 3000 Sats) and wish to spend 13000 Sats from your balance, how do you utilise coin control to freeze part of these UTXOs since you need 98% of the overall balance?


This link led me to a wall.

That is one of the advantages of coin control. Instead of wasting money on fee by spending UTXOs that are small, you can easily use coin control to freeze the UTXOs that are small. You can instead use coin control to only select the UTXOs to spend from anytime you want to make transaction.

I was unable to use https://jochen-hoenicke.de/queue/#BTC%20(default%20mempool),24h,weight to check it because it is representing the congestion period that you are referring to with lower fee, I mean when I set it to a year. But I did not see went up to 700 sat/vbyte around the time.

It wouldn't make any difference will it? I don't think so


Sure the the high priority blocks didn't exceed that amount?

The fee rate for high priority did not go up to 700 sat/vbyte if I can recall correctly.

Coin control to lock up some certain UTXOs. Although, addresses can be freezed in a way UTXO the addresses contain will be freezed, but for flexibility, coin control can be used to freeze certain UTXOs, even if the freezed UTXOs belong to the same addresses of the UTXOs that you did not freeze.

Great thread, more of these threads on the local board to help educate us about the bitcoin technical knowledge.

To clarify the whole explanation by Charles-Tim in simple term you can save more fees by using taproot address when the number of inputs (sending addresses) are greater than the number of outputs (receiving addresse(s)), other than that the best address to use is the native segwit address.


The major reason for consolidating UTXOs is to generally save future transaction fees so it would not be proper to pay higher fees when consolidating the UTXOs. So the best time to actually consolidate is when the mempool is less congested probably with fees less than 5sats/vbyte.

If the number of UTXOs are much and maybe the wallet keeps selecting just too many for every transaction before you consolidate then you can use the coin control feature to lock some certain address from spending and probably use only two addresses to be spending from before consolidation

Although the fees are low, you will still be charged for the UTXOs generated regardless of the type of address used. It's important to understand that generating more UTXOs is harmful to your wallet and assets over time. A few months ago, network fees surged to 30,000 sats/vbs and higher, and this could happen again. I had about $30 in my Trustwallet and could not withdraw due to the level of UTXOs in my wallet and the fee rate as of then.


I used the mempool for transactions, therefore it's important to understand how it works and when to move on to the next block, as well as the time and block size. And, while it is not recommended to use low fees while consolidating, it will do a lot more good than leaving those UTXOs in your wallet. Use the standard charge rate and get into the next block as soon as possible.

It is worth knowing that the address type used also matters. If comparing segwit version 0 addresses (address that start from bc1q) with legacy addresses (addresses that start with 1. Sending from segwit to segwit address will save you 42% fee in a transaction of 1 input and 2 outputs. The more the inputs and outputs, the more the fee it will save up to 50% fee.

If you want to be receiving bitcoin. For instance you are NCAing weekly for a long time and you have more inputs. Pay-to-taproot addresses will save more fee when consolidating. The more the input the more the fee pay-to-taproot addresses will save if comparing it with segwit version 0. Although if comparing the same input and output between segwit version 0 and pay-to-taproot, segwit version 0 has slightly low fee. But for consolidating, pay-to-taproot comes will low fee.

What that should also be considered is the mempool congestion.
You can use https://mempool.space/ or https://jochen-hoenicke.de/queue/#BTC%20(default%20mempool),24h,weight to check the fee rate that would be required, but if you are consolidating, it is your coin, you can use cheaper fee rate. Use a wallet that supports RBF so that if the transaction is not confirmed, you can pump the fee.

For ease, you can use this bitcoin transaction size/byte and vsize/vbyte calculator next time: https://jlopp.github.io/bitcoin-transaction-size-calculator

https://bitcoinops.org/en/tools/calc-size/

Segwit version 0 are addresses that start from bc1q
Pay-to-taproot is the segwit version 1, with the addresses that start from bc1p