Futures commissions are almost always quoted per round turn, or occasionally per side (half a round turn). Comparing brokers means checking which convention they use and whether exchange and clearing fees are included or extra.
Because futures costs are fixed per contract rather than a percentage, they fall as a share of the trade when you use larger contracts and rise when you scalp micros.
Example: $4 per round turn on ES with a 10-point average winner ($500) is 0.8% of the gross. The same $4 charged against a 10-point MES winner ($50) is 8%.
Related: exchange-fee, micro-futures, scalping, slippage, expectancy