Bitcoin Forum

Was trying to understand UTXO and landed up on the below link:
https://statoshi.info/dashboard/db/unspent-transaction-output-set

In the first graph it shows the total TX with unspent outputs. If this graph is low that means the spent transaction are more than the unspent. Is that what it means? Or I have read it wrong.

Also, the third chart Size of Serialized UTXO set is related to the bytes in a transaction. This bytes are used to calculate the fee. Is it so? Please help me understand

UTXO or unspent transactions referred to the received transaction which you didn't spend yet. Assume you have 1 BTC which you have received within 2 times, 0.60 BTC once and 0.40 BTC later. Here, the UTXO is 2. Is this what you are looking for?

UTXO stands for Unspent Transaction Outputs.
all we have in bitcoin are transactions, the whole blockchain is these transactions chained together.

the upper left chart is showing the number of transactions that created an output and that output is not yet spent. we can have 1 transaction that creates multiple outputs but it counts that transaction as one.

the upper right one is the total of those outputs so in that transaction example it counts the outputs instead of the whole transaction which is why the number is bigger.

the bottom left one is showing the entire UTXO set that the nodes store and belongs to the entire history of bitcoin, those outputs that are not yet spent. and the size is the size of that database in memory. which is the sum of raw bytes.

no. your fees are calculated based on YOUR transaction size not the transaction output your are spending and this size is those outputs added together.

In other others, just organizing what others said before:

Every transaction you received creates an input. IF you received btc 4 times, 0.25 each, you will have 1 BTC total, but 4 inputs.

Every address that you want to send BTC will be one output in your transaction. usually you will have 2 outputs, one for your destination and one back to you, as a change address (because inputs are not divisible).

The total size of your transaction will be determined by the number of inputs and outputs.

For example, if you want to send 0.3 BTC, you will have 2 inputs (0.25 btc each) and 2 outputs (0.3 destination and 0.2 back to you as change).

You can simulate the total cost of your transactions here: https://www.buybitcoinworldwide.com/fee-calculator/

Instead of trying to explain to you with my sub zero effort, I'd rather link you to this place :
https://learnmeabitcoin.com/glossary/utxo

Here's an alternate explanation targeted towards crypto literate noobs.
https://coincentral.com/utxo-beginners-explainer/

Go read what UTXO is first. Then when you get a grasp of what you are asking, you can check out the current number of UTXO's that are unspent here : https://www.blockchain.com/en/charts/utxo-count


I hope this satisfied the inner cat in you.

Thanks a lot. You cleared my confusion between top left and top right chart having difference on there value. :)