The round trip is the right unit for a trade. It starts when you buy and ends when you sell. Money has a longer journey than that. It starts in a bank account and, sooner or later, it goes back to one. The steps on either side of the trade have costs too.
Getting in
Before a coin can be bought, money has to arrive in a form the venue trades. That can mean a deposit, a conversion from one currency into another, or a purchase of a stablecoin first. Each step may carry a charge or a spread. A conversion priced with a markup looks free on the receipt for the same reason a commission-free trade does. A markup in the price versus a commission covers that pattern.
Moving between places
Crypto can be moved from a venue to a wallet, from one chain to another, or between venues. Each movement is a transaction on a network, and networks charge a fee to process one. A venue may add a withdrawal fee of its own. Moving between chains through a bridge adds another transaction at each end.
These fees are mostly fixed per transaction. They do not scale with the amount. That makes them heavy on small sums and light on large ones, which is the opposite of how a spread behaves.
Network fees and trading costs are different bills
It helps to keep the two apart. A trading cost is paid to the market or the venue for the exchange itself: spread, markup, fee, impact. A network fee is paid to the chain for recording the transaction. On an exchange or in a broker app you mostly meet the first kind. On-chain you meet both on every trade, and a transaction that fails can still cost the network fee. Gas fees are a trading cost goes into how the fixed fee shapes trade size.
Getting out
The exit side mirrors the entry. Selling the coin is the last leg of the trade. Converting the proceeds and withdrawing them are further steps, each with a possible charge. A profit measured at the moment of the sale is larger than the profit that reaches the bank.
Why it gets missed
These costs are paid at different times, in different places, sometimes in different currencies. None of them appears next to the trade. A trader who records only the buy and the sell will find that the account grows more slowly than the trade log says it should. The gap is the loop around the trade.
Counting the whole loop
The practical step is to measure from bank to bank once, for the route you actually use. Many of these costs are paid per movement and not per trade, so they shrink as a share when money stays put and trades many times, and they grow when money moves often. The trade itself is measured by its round trip. The NoVo Crypto Market Map ranks that figure on each coin from Robinhood’s own disclosed markup. The true cost of a crypto round trip covers the trade’s own costs in full.