Two commissions, set separately
The listing commission pays the brokerage that markets the home. The buyer-agent commission, where one is offered, pays the brokerage that brings the buyer. Since August 2024 those are separate negotiations rather than a single split, so the calculator lets you set each side instead of assuming one total.
A seller who offers nothing to the buyer side should expect the buyer to fund their own agent, which usually shows up as a lower offer rather than a saving. The question is not whether the fee is paid but who pays it and whether the price reflects it.