Bitcoin testnet fee is higher than sent amount

NotATether

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Quote from: LoyceV on February 05, 2022, 12:31:23 PM

Most likely: you (or your wallet) choose that fee. Just like in Bitcoin, there's no upper limit in the fee you can pay, and considering you're sending a small amount, the required fee can be higher if the network is congested.

I have just made an Electrum transaction from testnet and the fee given to me was just 1 sat/byte. It has been like that for the past few weeks as well. So that particular wallet doesn't have this problem.

o_e_l_e_o

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Quote from: adamcro on February 06, 2022, 04:58:48 AM

That's why I'm coding, it's easier to learn when I actually work on it and building it

Fair enough. Just make sure you stick with testnet until you are absolutely sure you know what you are doing then. Don't want to end up like the guy who made this transaction and spent 291 BTC in fees to move 0.0001 BTC: https://mempool.space/tx/cc455ae816e6cdafdb58d54e35d4f46d860047458eacf1c7405dc634631c570d

You can use a tool such as this one - https://live.blockcypher.com/btc-testnet/decodetx/ - to decode your raw transaction and check it is sending the coins where you want it to before you broadcast it.

adamcro

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Quote from: o_e_l_e_o on February 06, 2022, 04:42:57 AM

Quote from: adamcro on February 05, 2022, 06:20:54 PM

This is very very helpful. I did not know blockchain works like that. It's not like I have an address A with 1 BTC and I want to send 0.5BTC to address B, so after that address A will be left with 0.5BTC, what actually happens is that address A is left with 0BTC and 0.5BTC goes to fee

I would recommend having a read of this page: https://learnmeabitcoin.com/beginners/outputs. It very clearly breaks down the concepts I described above, that you can only spend an entire output (or multiple outputs), if you don't want to spend the full value to the other party then you need to specify to send some back to yourself as change, and whatever is left over that you haven't specified a destination for gets used as the fee.

I would also suggest, though, that since you don't have a firm grasp yet on how outputs and transactions work, that you should use a client such as Electrum which will do all this for you in the background, rather than trying to build a transaction manually and ending up losing large amounts of coins.

That's why I'm coding, it's easier to learn when I actually work on it and building it

o_e_l_e_o

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Quote from: adamcro on February 05, 2022, 06:20:54 PM

This is very very helpful. I did not know blockchain works like that. It's not like I have an address A with 1 BTC and I want to send 0.5BTC to address B, so after that address A will be left with 0.5BTC, what actually happens is that address A is left with 0BTC and 0.5BTC goes to fee

I would recommend having a read of this page: https://learnmeabitcoin.com/beginners/outputs. It very clearly breaks down the concepts I described above, that you can only spend an entire output (or multiple outputs), if you don't want to spend the full value to the other party then you need to specify to send some back to yourself as change, and whatever is left over that you haven't specified a destination for gets used as the fee.

I would also suggest, though, that since you don't have a firm grasp yet on how outputs and transactions work, that you should use a client such as Electrum which will do all this for you in the background, rather than trying to build a transaction manually and ending up losing large amounts of coins.

nc50lc

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Quote from: adamcro on February 05, 2022, 06:20:54 PM

-snip- I did not know blockchain works like that. It's not like I have an address A with 1 BTC and I want to send 0.5BTC to address B, so after that address A will be left with 0.5BTC, what actually happens is that address A is left with 0BTC and 0.5BTC goes to fee

A well-written single-address client will do that (send the change to the same address), but most wallets will use a "change address" for the remaining 0.5BTC.

I guess that API works like coinb.in which requires you to manually add a 'change address', or it'll use the remaining funds as fee.

adamcro

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Quote from: o_e_l_e_o on February 05, 2022, 04:19:47 PM

Quote from: adamcro on February 05, 2022, 01:02:09 PM

Isn't fee the difference between the sum of inputs and sum of outputs?

Correct. Whatever amount of bitcoin you don't specify an output for will be consumed as a fee.

In the first transaction you linked, your input was 8000 sats and you only specified a single output of 2000 sats, so the remaining 6000 sats was used as a fee. If you did not want to spend all that on a fee, then you should have specified an additional output to a change address of say 5500 sats, leaving 500 sats unaccounted for which would have been taken as the fee.

Remember that if you try to send 2000 sats, bitcoin cannot "skim" 2000 sats from an available input. It must spend the entire input, and so you must specify a destination for all the coins in that input you do not wish to be spent as a fee.

This is very very helpful. I did not know blockchain works like that. It's not like I have an address A with 1 BTC and I want to send 0.5BTC to address B, so after that address A will be left with 0.5BTC, what actually happens is that address A is left with 0BTC and 0.5BTC goes to fee

dkbit98

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Quote from: adamcro on February 05, 2022, 12:43:16 PM

One is Tatum.io wallet builder, the other is some app on Google Play for testnet

I never heard about Tatum wallet but from what I see this is not free service or it can be free but with some limitations, and one of them is that you can't adjust fees.
You would need to purchase Enterprise package to get this option enabled (that is more than 49$ per month you need to pay for Basic package).
You can use Electrum wallet with testnet with manual fees, other wallets with this option are Coinomi and Trezor hardware wallet.
If you want to check fees for Bitcoin testnet before sending transaction check out mempool.space website:
https://mempool.space/testnet

o_e_l_e_o

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Quote from: adamcro on February 05, 2022, 01:02:09 PM

Isn't fee the difference between the sum of inputs and sum of outputs?

Correct. Whatever amount of bitcoin you don't specify an output for will be consumed as a fee.

In the first transaction you linked, your input was 8000 sats and you only specified a single output of 2000 sats, so the remaining 6000 sats was used as a fee. If you did not want to spend all that on a fee, then you should have specified an additional output to a change address of say 5500 sats, leaving 500 sats unaccounted for which would have been taken as the fee.

Remember that if you try to send 2000 sats, bitcoin cannot "skim" 2000 sats from an available input. It must spend the entire input, and so you must specify a destination for all the coins in that input you do not wish to be spent as a fee.

adamcro

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Quote from: Charles-Tim on February 05, 2022, 12:51:09 PM

Quote from: LoyceV on February 05, 2022, 12:31:23 PM

Most likely: you (or your wallet) choose that fee. Just like in Bitcoin, there's no upper limit in the fee you can pay, and considering you're sending a small amount, the required fee can be higher if the network is congested.

I was thinking it could be because of the transaction weight before but by tracking the txid, you are very right, adamcro definitely customized the fee.

Or maybe he is using a non-reputable testnet wallet, but I doubt that because the fee using testnet is very low.

I wish I customized the fee. I guess Tatum.io customized, because I'm using their API

Isn't fee the difference between the sum of inputs and sum of outputs?

Charles-Tim

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Quote from: LoyceV on February 05, 2022, 12:31:23 PM

Most likely: you (or your wallet) choose that fee. Just like in Bitcoin, there's no upper limit in the fee you can pay, and considering you're sending a small amount, the required fee can be higher if the network is congested.

I was thinking it could be because of the transaction weight before but by tracking the txid, you are very right, adamcro definitely customized the fee.

Or maybe he is using a non-reputable testnet wallet, but I doubt that because the fee using testnet is very low.

Using testnet means you are not using real bitcoin, real (mainnet) bitcoin addresses start from only bc1, 3 or 1.

adamcro

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Quote from: LoyceV on February 05, 2022, 12:40:21 PM

Quote from: adamcro on February 05, 2022, 12:36:54 PM

I created this transaction with different wallet and fee is different

Which wallets are you using? See if they allow to customize the fee.

One is Tatum.io wallet builder, the other is some app on Google Play for testnet

LoyceV

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Quote from: adamcro on February 05, 2022, 12:36:54 PM

I created this transaction with different wallet and fee is different

Which wallets are you using? See if they allow to customize the fee.

adamcro

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I created this transaction with different wallet and fee is different https://www.blockchain.com/btc-testnet/tx/6cbfc22755c71a2393100a9646905d03f0384f6989edb08ba560ad9673f8e50e

LoyceV

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Most likely: you (or your wallet) choose that fee. Just like in Bitcoin, there's no upper limit in the fee you can pay, and considering you're sending a small amount, the required fee can be higher if the network is congested.

adamcro

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I was wondering why is fee higher than sent amount https://www.blockchain.com/btc-testnet/tx/079b8071417b0f1ae6a859fdbba11dfa0df99c96101b80dbff054ec687beebac

I sent 0.00002 and fee was 0.00006, why is that?

Topic: Bitcoin testnet fee is higher than sent amount (Read 187 times)