How far does the price need to move in your favor to break even after round-trip fees?
Use the fee comparator to find the taker fee in basis points for your venue. Most CEX perps charge 4-7 bps taker.
On a 10-bps round-trip cost, you need a 0.1% favorable move just to break even. For a scalper aiming at 0.3% per trade, that's 33% of the trade's gross profit eaten by fees. The only way to make scalping work is to either (a) use maker orders (typically 30-60% lower fees) or (b) trade larger moves where the fee becomes a small fraction of the gross.
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