Blockchain.info. How to calculate a fee?

[sipungora]

Hi,

Blockchain.info provides a possibility to adjust a fee. This seems super, but it is almost useless without knowledge about a size of a transaction.

I have serious reservations about default values provided by Blockchain.info.

Could someone please explain, how to calculate a fee more or less exactly to neither over- nor underpay?

[1713873645]

1713873645

[1713873645]

1713873645

[1713873645]

1713873645

[TechPriest]

Could someone please explain, how to calculate a fee more or less exactly to neither over- nor underpay?

Just see here https://bitcoinfees.earn.com/ . It show sat/byte. So, just check needed fee for you and then type into necessary field. That's all. System will make everything other by itself.

[bob123]

This seems super, but it is almost useless without knowledge about a size of a transaction.
Could someone please explain, how to calculate a fee more or less exactly to neither over- nor underpay?

For a less exactly option you can use the service of estimatefee (https://estimatefee.com/).
Depending on the amount of inputs/outputs you will get an estimation of a required fee to get your TX confirmed within X blocks.

To calculate the size more accurately you need to know what kind of address you are spending from (Legacy / Segwit (and whether bech32 or P2WPKH, P2WPKH/P2SH)
and the amount of inputs / outputs your transaction is composed of. Afterwards you can use any service of your choice to look for an appropiate fee (e.g. estimatefee or https://bitcoinfees.earn.com/).

Usually most wallet providers let you to choose the fee in sat/B. Therefore you don't need to know the size of the TX to set an appropiate fee.
Just check the links out.

[sipungora]

Could someone please explain, how to calculate a fee more or less exactly to neither over- nor underpay?

Just see here https://bitcoinfees.earn.com/ . It show sat/byte. So, just check needed fee for you and then type into necessary field. That's all. System will make everything other by itself.

To reasonably use this I need to know a size of a transaction. But I can get it only after I press the button "Send", so after a fee is already set and the transaction is out of my control.

[sipungora]

This seems super, but it is almost useless without knowledge about a size of a transaction.
Could someone please explain, how to calculate a fee more or less exactly to neither over- nor underpay?

For a less exactly option you can use the service of estimatefee (https://estimatefee.com/).
Depending on the amount of inputs/outputs you will get an estimation of a required fee to get your TX confirmed within X blocks.

To calculate the size more accurately you need to know what kind of address you are spending from (Legacy / Segwit (and whether bech32 or P2WPKH, P2WPKH/P2SH)
and the amount of inputs / outputs your transaction is composed of. Afterwards you can use any service of your choice to look for an appropiate fee (e.g. estimatefee or https://bitcoinfees.earn.com/).

Usually most wallet providers let you to choose the fee in sat/B. Therefore you don't need to know the size of the TX to set an appropiate fee.
Just check the links out.

Thank you very much! But how could I know all of these? Or you mean I should start an investigation for every spending address?

What do you mean by the amount of in/outputs? Are these bitcoins or bytes?

The Blockchain.info doesn't provide such info.

Could you please provide an example?

[bob123]

Thank you very much! But how could I know all of these? Or you mean I should start an investigation for every spending address?

It depends on your wallet which addresses are generated.
Blockchain.info standard wallet generates P2PKH i think (Those starting with 1... ).

What do you mean by the amount of in/outputs? Are these bitcoins or bytes?

Whether bitcoins, nor bytes.
Its the amount of inputs your transactions consists of. You can read more here: https://en.bitcoin.it/wiki/Transaction#Input

The Blockchain.info doesn't provide such info.

To get the actual amount of inputs you need a wallet with more functionality. Electrum (https://electrum.org/#home) is suitable.

Could you please provide an example?

In your case (assuming P2PKH), the size of a transaction would roughly be:

Code:

#IN * 180 + #OUT * 34 + 10 +/- #IN

where: #IN = number of inputs, #OUT = number of outputs

With 1 input and 2 outputs your TX would be at about 257 to 259 bytes.

[HCP]

To reasonably use this I need to know a size of a transaction. But I can get it only after I press the button "Send", so after a fee is already set and the transaction is out of my control.

No, you don't need to know the size of the transaction. B.info offers you the ability to specify the fee "rate" in sats/byte... as long as the rate you input is similar to the rates specified by either https://bitcoinfees.earn.com/ or https://btc.com/stats/unconfirmed-tx then, your transaction should not get stuck, as the total fee will be calculated correctly for your transaction size.

[sipungora]

To reasonably use this I need to know a size of a transaction. But I can get it only after I press the button "Send", so after a fee is already set and the transaction is out of my control.

No, you don't need to know the size of the transaction. B.info offers you the ability to specify the fee "rate" in sats/byte... as long as the rate you input is similar to the rates specified by either https://bitcoinfees.earn.com/ or https://btc.com/stats/unconfirmed-tx then, your transaction should not get stuck, as the total fee will be calculated correctly for your transaction size.

https://i.imgur.com/qIqEy2m.png

Super! Thank you very much.

[Kakmakr]

You should never just use the fees, recommended by Blockchain.info. I have noticed that the fees recommended by them are a lot higher than the actual fees that would be required to get your transaction confirmed.

Their fee estimation is a bit inflated, so it is recommended to configure your own. ^smile^