I've looked through the different threads after a search for "high fee", but I don't seem to get the answer I need.
I have just made a donation (= no haste going through the block chain) of ≈ €20,00 with the "Fee" slider set to the lowest position (= 25 blocks, I believe). Before I'd paid attention to what was going on I had paid ≈ €10,00 in fees. Which is obviously ridiculous. The transaction did go through pretty quick, though, much faster than expected and... needed.
One thread I found here suggests that setting the preferences to "Edit fees manually". Right now I have only "Use dynamic fees" and "Propose Replace-By-Fee = Always." In a case like this one, how can I know what's the right fee to apply while trying to avoid the transaction getting stuck forever (I've had this happen once, it took one whole month before it went through, a real hassle for both sides getting the BTCs back).
Fees change according to demand and supply of space on the blockchain. When you set fees to dynamic that means electrum queries electrum servers for fee estimates and then sets a fee based on what it learns. Therefore the fees electrum sets are based on market conditions and are the best fees for a novice user.
Replace by fee (RBF) is a setting that marks your transaction as replaceable. It is used in case your transaction gets stuck due to low fees (which shouldn't normally happen with dynamic fees). In such a situation it is possible to bump the fee of your transaction by replacing it with a new transaction that pays a higher fee. Marking a transaction as RBF doesn't cost you anything but it does provide you with a safety net in case a transaction gets stuck due to low fees.
Now regarding how fees are calculated you should know that it is the size of the transaction in bytes that matters not the amount transferred. You are paying for space on the blockchain so the more space your transaction takes the more you have to pay. Transactions with lots of inputs and outputs pay more than transactions with fewer inputs and outputs.
So now that I've explained all of the above lets address the question of why you had to pay such a large fee. Edit LOL because fees are just very high right now! What can I say? Bitcoin is expensive to use!
In future you can click on preview on the send tab to see how much in fees you will be paying before you send the money.
What I need to know then is the following:
1. If in this concrete case (€20) the €10 fee is related to 25 blocks, would a fee of, say, €2 be related to 125 blocks?
2. Where is it possible for a commoner to see the time it would take to get through 100, 125, 150 blocks, or whatever?
3. From how many blocks is there a risk of my transaction never getting through?
Sorry if I'm not asking these questions the right way, but again I only want to use BTC as a payment method, taking them out my pocket as I would a Euro bill.
1. IDK depends on market conditions. It does not scale up and down linearly. Besides electrum only offers the 25 block delay. There was talk of expanding that to slower confirmation times. Maybe in the next release.
2. A block happens on average every 10 minutes but it can vary widely. The protocol tries to ensure a 10 min average time between blocks over every 2 week period.
3. Transactions are atomic so if it doesn't get picked up by a miner and incorporated in a block it'll eventually be forgotten and the funds will show up back in your wallet. This can take weeks though. However if you have RBF enabled you can increase the fee retroactively. That means you can low ball the initial fee and later on bump it higher if it doesn't confirm.
The best thing you can do is to keep an eye on the mempool using sites like the earn.com one and the ones below:
https://tradeblock.com/bitcoin/https://btc.com/stats/unconfirmed-txDo your transactions on days when the mempool is less congested and fees have fallen. That tends to be on weekends although not this weekend obviously
