I develop trading bots. Our historical tests used a fee of 0.06% per side. When I checked the executions from one of my live accounts, though, the volume-weighted fee rate actually paid was about 0.0801%.

That looks like a small difference. But fees apply to every fill, and a bot can generate a lot of them. I wanted to answer two questions: where did the different rate come from, and how much would it change one backtest?

What the account actually paid

I took a Bybit crypto futures execution export covering August 29 to October 25, 2026. It contained 3,204 trade executions. Those are fills, not completed trades: a single order can fill in several parts.

The executed notional was about 323,731.67 USDT. Trading fees totalled about 259.44 USDT.

To calculate the average rate, I divided the fees paid by the executed notional:

259.44 / 323,731.67 × 100% ≈ 0.0801%.

Funding payments for holding futures positions were excluded from that calculation.…