I sent $40 to some address and it's been 8+ hours and still no confirmation, so I don't know what to do. When I was about to send the payment, electrum's slider was on far left, meaning the smallest fees and "within 25 blocks", but seems like it takes forever instead. I saw
https://bitcoinfees.21.co/, but there isn't BTC/kB which is present in Electrum client, so I don't know how to calculate the optimal fee in order not to get stuck like now. From what I've seen on website, there is BTC per byte.
I don't recommend using the slider all the way to the left. That is a low fee and it could take 25+ or more blocks to confirm which could be a very long time. Electrum seems to do a pretty good job when leaving the slider in the middle and if you need a very quick confirm, slide it to the right. If you want more control, you can specify a manual per KB fee in the preferences but I've found that the dynamic fees work pretty well most of the time. Just don't slide it to the left unless you are prepared to wait a long time.
