How to calculate bitcoin transaction size and fees

[bitmover]

I just remembered something which is related to the subject of having many inputs.

Electrum allows you to chose which input to use. There is an option "coins" which let's you see all your inputs and choose which one to spend. This is particularly interesting to do if you have many inputs, because you can consolidate as many as possible in a transaction of fees are low, or use the minimum as possible of they are high.

Remember that any additional BTC will become a new input that will go to a change address.

[1715392371]

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[1715392371]

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[1715392371]

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[1715392371]

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[naska21]

Well, but one can combine various  inputs from both legacy and segwit (p2sh, bech32) addresses into one transaction. Does anyone know how to calculate the transaction fee in this case? Is there any formula to do that? I have asked this question in Russian section and they pointed me to https://coinb.in/#fees  site that could help in estimation. Regardless,  I would like to  have the reliable   mathematical formula to control the fee.

[RapTarX]

Well, but one can combine various  inputs from both legacy and segwit (p2sh, bech32) addresses into one transaction. Does anyone know how to calculate the transaction fee in this case? Is there any formula to do that? I have asked this question in Russian section and they pointed me to https://coinb.in/#fees  site that could help in estimation. Regardless,  I would like to  have the reliable   mathematical formula to control the fee.

For controlling the fee, I guess, you don't need to know the mathematical formula. However, the formula is for calculation of transaction size, not for the fees. Fees can be found at your pointed web, you can pay less or more, it's your choice.

[naska21]

Well, but one can combine various  inputs from both legacy and segwit (p2sh, bech32) addresses into one transaction. Does anyone know how to calculate the transaction fee in this case? Is there any formula to do that? I have asked this question in Russian section and they pointed me to https://coinb.in/#fees  site that could help in estimation. Regardless,  I would like to  have the reliable   mathematical formula to control the fee.

For controlling the fee, I guess, you don't need to know the mathematical formula. However, the formula is for calculation of transaction size, not for the fees. Fees can be found at your pointed web, you can pay less or more, it's your choice.

To be clear: it seems to me that general formula is fee = size x (satoshies/byte) but  I wanna have formula for size when various inputs (legacy and segwit) are combined into single transaction.

[Mehr Sher]

There are many ways on how we can calculate these things but the best way is to use Crypto Calculator, as this just simplifies everything for everyone.

It just ensures that we are able to work nicely and easily without any major trouble at all. With this we can easily do well and able to get the right calculation, especially if we are dealing and doing transaction is bigger numbers. It’s almost necessary for everyone to get this right.