Most trading fee calculators show you two numbers: the dollar amount and the percentage of notional. Both are correct. Neither is useful.

Here's the problem.

Dollar-denominated fees hide the real cost

Say you're trading Bitcoin perpetuals on Bybit. Taker fee is 0.055% each side. You buy $10,000 notional.

Entry fee: $5.50

Exit fee: $5.50

Round trip: $11.00

Does that matter? Impossible to say without knowing one more number: how much are you risking on this trade?

If your stop is $200 away (2% of position), your risk is $200. The $11 fee is 5.5% of your risk. That's 0.055R — acceptable for most strategies.

If your stop is $50 away (0.5%), your risk is $50. The $11 fee is 22% of your risk. That's 0.22R. On a 1:2 trade, your effective R:R just became roughly 1:1.56. At 100 trades, you've given up 22R to the exchange.

Same fee, same position size, completely different impact depending on your actual risk.

What R multiples expose

The R multiple framework comes from Van Tharp's work on expectancy.…