Reading the result
What the numbers above actually mean, and what they don't cover.
PnL and ROE are not the same number
PnL is the dollar result of the trade. ROE is that same result expressed as a percentage of the margin you posted, not of the position size. The two tell you different things, and leverage only moves one of them.
At 10x leverage, a 5% move in your favor is a 50% ROE. Leverage does not change how many dollars the market pays you for a given price move — the quantity you hold does that. What leverage changes is how much of your own capital was standing behind those dollars, which is what ROE measures.
The same scaling works against you. A 5% adverse move at 10x is a 50% ROE loss, and at higher leverage a much smaller adverse move reaches 100% — the point where the position is liquidated and the margin is gone.
What fees actually cost you
The calculator charges the fee rate twice: once on the entry notional, once on the exit notional. At low leverage that is a small dent. At high leverage it is not, because the notional grows with leverage while your margin does not.
At 50x, a round-trip at 0.05% per side is 5% of your notional in fees — which is 2.5x your margin. A position needs to move in your favor by more than that just to break even. Higher leverage does not just raise the risk of a larger loss; it raises the bar the trade has to clear before fees stop eating the result.
This is also why the preset fee buttons above matter more than they look: the gap between a 0.02% maker rate and a 0.055% taker rate scales with notional the same way the rest of the fee bill does.
What this calculator leaves out
Funding is included, at the current rate held constant for your whole holding period — see the Funding row above. What is not included is slippage on entry and exit, and partial fills on either side.
The current funding rate is also not a forecast. It can and does change between settlements, and a position held for days is more exposed to that drift than one held for hours.