Brokerage fees are calculated in different ways. It would be impossible to list all of them here. However, here are the types of fees that you need to be aware of:
Trading commissions
Maintenance fees
Equity fees
Additional charges
Trading commissions may be based on a percentage or a fixed fee per trade. However, a lot of online brokerages now charge no trading commissions.
Maintenance fees are charged to maintain your account. These are annual fixed fees that you must pay to use the brokerage. Equity fees, on the other hand, are usually a percentage of your total account value and charged annually. Some brokerages do not charge this fee, so you may be better off using them if you have a lot of money to invest.
Lastly, other charges include anything that you may incur when using additional services provided by the brokerage. For example, zero-commission brokers usually charge a lot of money if you need assistance (e.g. a phone call to a broker) when placing an order.