Visual Presentation - Input, Output, Coin Control & Change address

[RapTarX]

This terms are very much known if you are using bitcoin in your daily life or you are playing a little with bitcoin. These are not much important if you are an end user who only spending bitcoin for daily life but if you are a bit interested how things going on- you must have those knowledge.

In the above image, imagine, you have received total of 1 BTC from Bob. Bob once sent you 0.30 BTC and later sent 0.7 BTC. Now, you want to send 0.4 BTC to one of your friend, from where you are taking the BTC? Bob's output, isn't it? So, Bob's output is your input when you are sending 0.4 BTC to your friend. Here, we have used the both of Bob's Output.

Input- Bob's Output = From where the BTC came from.
Output- Where BTC is heading to.
If you have a closer look at the above image, it will be clear to you.

In the above image, you have 1 BTC which Bob has sent to you. Now, you want to send 0.4 BTC to your friend. If you want, you can use one of the output of Bob- 0.7 BTC and this can be done through coin control, so, coin control is giving us the power to which output of Bob we want to spend. Now, since you will send 0.4 BTC from 0.7 BTC, you have some changes, right? Because you can't deduct 0.4 BTC from your 0.7 BTC input. Imagine, you have one single note of $70. You have purchased something worth of $40, now the shopkeeper will give you a change of $30.
In this case, you are telling like- I am giving 0.70 BTC, from where 0.40 BTC will be sent to my friend and the rest will be sent to my address (This address is your change address.)

I guess I have not done any mistake or used any misconception, If I have used, you can correct me. I always try to write something in a very easy way so that, a very newbie can learn something from my article.

[1715054532]

1715054532

[coupable]

Nice presentation, but it seems to me a little bit complicated for noobs.
I want to add some notes:
- It would be easier to explain inputs and outputs from any transaction details in any block explorer.
- Change address is what makes noobs confused when looking at a transaction outputs, some wallets give its users the ability to look at all the addresses at once and observ how much each one has. In electrum, as example, change addresses are in the bottom of the address list and are categorized as "change addresses".
- Not all the wallets give users the feature of "Coin Control" , so it would be complicated "useless" for noobs to look for. But, it's important  , imo , to understand that the "Coin Controle" is technically possible.

[bitmover]

I agree with coupable
 It is much easier to understand using any blockexplorer. For example look here. One transaction with one input  generating 2 outputs

Source:https://atomicwallet.io/block-explorer
It was a good explanation after all.

Few people understand this idea of inputs and outputs

[nakamura12]

Nice presentation, but it seems to me a little bit complicated for noobs.
I want to add some notes:
- It would be easier to explain inputs and outputs from any transaction details in any block explorer.
- Change address is what makes noobs confused when looking at a transaction outputs, some wallets give its users the ability to look at all the addresses at once and observ how much each one has. In electrum, as example, change addresses are in the bottom of the address list and are categorized as "change addresses".
- Not all the wallets give users the feature of "Coin Control" , so it would be complicated "useless" for noobs to look for. But, it's important  , imo , to understand that the "Coin Controle" is technically possible.

I agree what you just explain but I don't think it's impossible for noobs to understand this presentation after all noobs are here to learn that they haven't know yet. Anyway, the op's presentation is also helpful for noobs in my honest opinion even if it can only help noobs learn slowly.

[Wexnident]

Additional would probably explain what Coin control and Change address is and what they are used for? I kind of recognize the Input Output Diagram, iirc, I saw it from the original paper of Satoshi from his proposal of Cryptocurrency. Besides, Input and Output logic is already common sense so I suppose no need to explain what they mean, but for the other two, I rather think it is.
Anw, concerning the info explained, It's rather detailed and if the topic is limited here, other than defining the terms, I'd suppose everything was explained well.

[RapTarX]

In electrum, as example, change addresses are in the bottom of the address list and are categorized as "change addresses".

You can also use your input address (where you have the BTC) as change address in Electrum. In some other wallet, change address can be modified into any of your address.

- Not all the wallets give users the feature of "Coin Control" , so it would be complicated "useless" for noobs to look for. But, it's important  , imo , to understand that the "Coin Controle" is technically possible.

I haven't used much wallets, as far as I know, all software wallets for PC have this option.

I agree with coupable
 It is much easier to understand using any blockexplorer. For example look here. One transaction with one input  generating 2 outputs

Using the block explorer, it's easy to understand the output, but the inputs are actually hidden here, I tried to explain how inputs are originated by showing the output from previous transaction(Bob's output).
I wanted to show something like this- https://www.blockchain.com/btc/tree/2893660

Additional would probably explain what Coin control and Change address is and what they are used for?

I guess I have shared explanation on both of these terms, in a simple way in the 2nd part.

[coupable]

Totally ok with this graph for anybody {Pros & Cons) to figure out different parts of a bitcoin transaction, expect for the "coin control" :

Coin control : in simple words, it's the ability to choose which address you want to spend from. As explained above, major desktop btc wallets have this feature. But, may be not in mobile wallets; i used electrum for mobile but don't remember see this option, also BitPay.

[bitmover]

Using the block explorer, it's easy to understand the output, but the inputs are actually hidden here, I tried to explain how inputs are originated by showing the output from previous transaction(Bob's output).

Blockchain.com explorer indeed hide the inputs of the same address

There is are some blockexplorer which don't hide them.
Take a look here

https://blockchair.com/bitcoin/transaction/b65d25c7a07bffaa95ba6e6bda3d1dc05a3c188c1f4e9d3ab4693b0e4f718ede
https://m.btc.com/b65d25c7a07bffaa95ba6e6bda3d1dc05a3c188c1f4e9d3ab4693b0e4f718ede

You can see that there are two inputs from the same address in both explorers

I won't make images because I am lazy, but you can check the links;)

[SFR10]

Since this is meant for newbies, I think a simpler explanation would be to compare it side by side with paper money ^{[real life scenario]}...

Blockchain.com explorer indeed hide the inputs of the same address

There is are some blockexplorer which don't hide them.
Take a look here

https://blockchair.com/bitcoin/transaction/b65d25c7a07bffaa95ba6e6bda3d1dc05a3c188c1f4e9d3ab4693b0e4f718ede
https://m.btc.com/b65d25c7a07bffaa95ba6e6bda3d1dc05a3c188c1f4e9d3ab4693b0e4f718ede

You can see that there are two inputs from the same address in both explorers

I can see both inputs on "blockchain's explorer" as well.

[pooya87]

Coin control : in simple words, it's the ability to choose which address you want to spend from.

that is not simple, that is incomplete and a little bit misleading.
coin control, as the name suggests, is "controlling" which "coins" you spend. in bitcoin we only have transaction outputs and that is what we are spending and these transaction outputs are sometimes referred to as coins.
so when you select "spend from address" feature in a wallet like Electrum you are actually selecting a group of "transaction outputs" aka "coins" to spend, but the wallet is abstracting that for convenience.

[bitmover]

I can see both inputs on "blockchain's explorer" as well.

Thanks for the update.
Blockchain com explorer used to hide different inputs from the same address. Thankfully it is not hiding anymore, as it is a nonsense and misleading to newbies.