What you actually pay
The statement: the fee is two percent. Which fee. There are at least four in a single order and they do not behave alike.
Bucket: DEPENDS
It depends on which fee you mean, on network conditions at the moment you transact, and on how many times value moves. Some are fixed percentages, some are set by an auction, and some are hidden inside an exchange rate.
The fees in one order
| Fee | Set by | Visible before you commit |
|---|---|---|
| Network fee on your deposit | You, bidding for block space | Yes, in your wallet |
| Market commission | The market, usually a percentage | Usually stated |
| Network fee on withdrawal | The market's policy | Sometimes |
| Exchange rate spread | Whoever converts | Rarely, and it is the quiet one |
| Any conversion between coins | The converter | Partly |
Why the network fee is not a percentage
It is a bid for space in a block, priced by transaction size in bytes rather than by value. So sending a small amount can cost the same as sending a large one, and a fee that is trivial on a big transfer can be a large fraction of a small one.
This is why fee advice from someone moving different amounts than you is useless. The percentage they experienced is an artefact of their amount.
The quiet one
The spread. Any conversion between currencies happens at a rate somebody chose, and the difference between that rate and the market rate is a cost that never appears as a fee. It is not itemised, it is not usually disclosed, and it can exceed all the explicit fees put together.
If you want to see it, compare the rate you were given against a public rate at the same moment. That comparison is the only way it becomes visible.
Why fee advice ages badly
Network fee levels move with demand for block space, and demand moves for reasons that have nothing to do with you. A figure that was generous last month can be too low today and wasteful next week. Any specific number written down anywhere is out of date by the time it is read.
Wallets estimate current levels because it is the only sensible way to do it. A wallet suggesting a fee is reading conditions now, which is more than any page can do.
What people get wrong
They budget for the headline percentage and are surprised by the total. The headline is usually the market commission, which is often the smallest of the four.
They also economise on the wrong one. Cutting the network fee to save a small amount can add hours of waiting, which is covered on the deposit time page. Meanwhile the spread goes unexamined.
The controllable part
The network fee on the way in, the number of times you move value, and whether you convert. Fewer movements means fewer fees. That is the whole optimisation and it is more effective than shaving any single number.
Questions people actually ask
Why did my small transfer cost so much proportionally?
Network fees are priced by transaction size in bytes, not by value. The same fee is a larger fraction of a smaller amount.
Which fee is usually the largest?
Often the exchange rate spread, because it is not itemised anywhere and nobody adds it up.