Inquiry

[Hasslong]

If i have only one utxo  in BTC on address1 and want to transfer to another address  2 , how to know my utxo size how many vbyte this utxo?

[Charles-Tim]

It depends on the address type. To calculate the transaction virtual size, you can use this calculator: https://jlopp.github.io/bitcoin-transaction-size-calculator/

[o_e_l_e_o]

When you create a transaction on Electrum, but before you sign it, the preview window will tell you how many vbytes your transaction is. If it didn't then you wouldn't be able to accurately calculate an appropriate fee.

[Pmalek]

It depends on the address type. To calculate the transaction virtual size, you can use this calculator: https://jlopp.github.io/bitcoin-transaction-size-calculator/

You are not wrong. The size does depend on the type of address sending and receiving the bitcoin, but that source you shared could be a bit frightening and hard to understand for a beginner. They might not know what all those different scripts and abbreviations mean or even what inputs and outputs are. A good wallet, displays all this before you broadcast your transaction. Since we are talking about Electrum here, the software displays the necessary data during the transaction creation process.   

[Husna QA]

If i have only one utxo  in BTC on address1 and want to transfer to another address  2 , how to know my utxo size how many vbyte this utxo?

I tried to complete some of the explanations above with screenshot examples. If you use Electrum (the example I use is version 4.4.6), the transaction size can be seen here:
- When clicking the Pay button to determine the Mining Fee:

- When clicking the Preview button:

[NotATether]

Generally, the difference in fees between different address types will just be a few dozen extra bytes counted in the fee or so (including all of the nuances of "vbytes" in this factor as well). In a normal market, where fees are not maddeningly high, the difference will only be a few cents maximum, depending on what fee rate you set for your transaction. And even now, it should not make much a difference unless you're sending to more than one address at once or you put more UTXOs in your transaction.