Trading fee impact
A 0.1% fee sounds negligible. Paid on both sides of a trade, fifty times, against a balance that is shrinking each time, it is not. This compounds it properly.
Why it compounds
Each side of each trade takes its percentage of whatever the balance is at that moment, so the drag is (1 − fee)2n across n round trips, not fee × 2n. The difference is small at ten trades and large at two hundred.
The figure assumes every trade breaks even before fees, which isolates the fee effect. It is a floor on the cost, not a prediction of your results.
The number that matters
“Gain needed per trip to stay flat” is the more useful output. At 0.1% per side you need roughly +0.2% per round trip simply to end where you started — before any view about whether the trade was right.
What this does not model
Maker/taker distinctions, volume tiers, spread, slippage and funding costs are all excluded, and all of them make the real figure worse. See the spread cost calculator for the next-largest component.
