Just need a quick explanation on a transaction fees question

[A.Delaney]

Basically I made a purchase in BTC on a website. The invoice had the purchase amount on it. Then in a note it said to make sure you send enough BTC to cover the transaction fees.

This was the first time I have ever sent BTC.

My wallet is a Trezor. In the drop down box it gives you a list to choose from regarding the transaction speed. Normal, fast, slow etc. Next to each speed rating there is an amount next to it in sat/B. I dont know what the B stands for. So I picked normal. That was 646 sat/b. I was sending .05591000 and it ended up sending .0593984 automatically.

 Why does the website remind you to include enough for the transaction fee? Don't you automatically pay the fee just to send it from your wallet? Did I need to add something extra?How do I know how much to add? They didn't tell me an amount. The website uses coinpayments to conduct the sales transactions. Is there a fee to receive it also that I needed to include? 

[A.Delaney]

Now I am afraid I did not send enough. My email from coinpayments says .04689000 btc.  I am short .00000902 BTC?

[pooya87]

the b stands for Byte.
when you send a bitcoin transaction the fee you pay depends on how big your transaction is in bytes. in other words you pay for the  data that you are sending and want to be included in the blockchain, that  data is your transaction. normally it is 226 bytes. but if you have received multiple payments and now want to spend them all, your transaction size will be bigger.

(edit: i may have made some calculation errors calculating the fees you paid)
you are paying 0.00348840BTC with 646 sat/b fee, so your transaction size was 540 bytes. which means you are spending more than 1 transaction output (received multiple payments).

as for amount you sent, you shouldn't look at the total sent. you should instead check the transaction to see how much you sent to the address they gave you and how much went to your change address.

your transaction should look something like this:
https://blockchain.info/tx/6930ca7e882fc53b722e14efc1cd29789ae12d7146c9a0978ac6e838a752590b?show_adv=true
you can see it is making a 0.1729BTC payment to the first address and getting 0.00102696 BTC back as change. and the fee is 0.00535181BTC

[A.Delaney]

the b stands for Byte.
when you send a bitcoin transaction the fee you pay depends on how big your transaction is in bytes. in other words you pay for the  data that you are sending and want to be included in the blockchain, that  data is your transaction. normally it is 226 bytes. but if you have received multiple payments and now want to spend them all, your transaction size will be bigger.

(edit: i may have made some calculation errors calculating the fees you paid)
you are paying 0.00348840BTC with 646 sat/b fee, so your transaction size was 540 bytes. which means you are spending more than 1 transaction output (received multiple payments).

as for amount you sent, you shouldn't look at the total sent. you should instead check the transaction to see how much you sent to the address they gave you and how much went to your change address.

your transaction should look something like this:
https://blockchain.info/tx/6930ca7e882fc53b722e14efc1cd29789ae12d7146c9a0978ac6e838a752590b?show_adv=true
you can see it is making a 0.1729BTC payment to the first address and getting 0.00102696 BTC back as change. and the fee is 0.00535181BTC

So if I send too much. I will get change back?

[Xynerise]

My wallet is a Trezor. In the drop down box it gives you a list to choose from regarding the transaction speed. Normal, fast, slow etc. Next to each speed rating there is an amount next to it in sat/B. I dont know what the B stands for. So I picked normal. That was 646 sat/b. I was sending .05591000 and it ended up sending .0593984 automatically.

The amount sent includes the miner fee.
If you're sending 1BTC, with a standard transaction size of 226 bytes (one input and 2 outputs) with the fee you paid, 646sats/byte, which amounts to 0.00145996 BTC, the total your wallet will send is 1BTC + the fee of 0.00145996BTC = 1.00145996BTC

 

Why does the website remind you to include enough for the transaction fee?

Bitcoin transactions are included in blocks of 1MB (4MB block weight with Segwit), and your transaction is "competing" with hundreds of thousands to be included.
There is only 1 block every 10 minutes, and if you do not include adequate fees then your transaction will be relegated for others with higher fees.

Don't you automatically pay the fee just to send it from your wallet?

Fixed fees are not recommended because you can either overpay or severely underpay, leaving your transaction stuck in the mempool.
That's why your wallet asks you to select the fee you want to use depending on how you need your transaction to confirm.

Did I need to add something extra?

No. You just need to pay the transaction fee for your transaction to be confirmed.

So if I send too much. I will get change back?

No. If you overpay fees you won't get "change" back.
This is why you should confirm your transaction before sending.

How do I know how much to add? They didn't tell me an amount.

Your wallet already showed you slow, normal and fast.
It calculates the recommended fee and you can usually trust it, but if you don't trust your wallet's estimation then use https://bitcoinfees.21.co to find out the current recommend fee for quick confirmation.

 

[efey39]

When you invest in Blockchain, you have to deal with crypto money processing fees. This is nothing new to you as you are on stock market stock exchanges, as well as for using third party services.

However, due to the decentralized nature of the crypto currencies, you must pay using a crypto network. The network must be encouraged to verify all operations in the block chain and you are paying a fee.

Therefore, there are three types of transaction fees when dealing with cryptographic currencies;

Fees traded on exchanges
Transaction costs
Wallet fees

[A.Delaney]

https://btc-bitcore1.trezor.io/tx/f1441e07ed956194d001ff4159b4b8d86e26e39c2ab16dcc842924f5fd5397bd

Please look at this link. Would the person receiving the payment get .05591646 BTC?

[Xynerise]

https://btc-bitcore1.trezor.io/tx/f1441e07ed956194d001ff4159b4b8d86e26e39c2ab16dcc842924f5fd5397bd

Please look at this link. Would the person receiving the payment get .05591646 BTC?

Yes, if the person is in control of the wallet address 3Lo5H7DLBTs4stnk1i6xMCQf7KHe7QswYF

[A.Delaney]

Ok good so last question.

When I log onto coinpayments . Under recent transactions it shows a payment to the recipient I was sending it to. The recipient uses coinpayments to process their sales transactions. It shows .04689000 btc under recent transactions. How come this amount is less? Do I still owe them more btc even though in the link I posted it shows the full amount of .05591646 btc was transferred?