Round-trip cost
Round-trip cost is the total fee for opening and closing one position — two fills, two fees. It is the honest unit for measuring what a trade costs, since no position stays open forever.
A single fee rate understates real trading costs because every position is eventually exited. The round-trip doubles the per-fill fee: enter and exit as taker at 0.06% and the position costs 0.06% × 2 of notional in fees, before slippage and funding.
Round-trip math exposes how strategy style drives costs. A scalper doing ten round-trips a day pays twenty fills' worth of fees daily; a swing trader might pay two per week. Same account size, wildly different fee bills — which is why fee sensitivity is mostly a function of trade frequency, not account value.
It is also the right frame for evaluating a rebate. A payback of 50–67% applies to every fill, so it scales one-to-one with round-trip count. The more round-trips your strategy produces, the more of your cost base the rebate recovers — with no change to how you trade.
Model your monthly round-trips →