A common commission split gives 60% to the agent and 40% to the broker, but the split could be 50/50, 60/40, 70/30, or whatever ratio is agreed by the agent and the broker. It is common for more experienced and top-producing agents to receive a larger percentage of the commission.
Both the seller's agent and the buyer's agent have agreements with their sponsoring brokers that specify the agent's cut of the commission. It can be a 50/50 split between the broker and the agent or any other split they choose.