Expense ratios vary depending on the type of investment you choose. Passive funds — like index mutual funds and index ETFs — generally come with extremely low expense ratios. A study by financial services firm Morningstar found the average index fund’s expense ratio was .12% in 2019. Expense ratios can be as low as 0% with Fidelity’s ZERO funds. Actively managed mutual funds and ETFs incur more costs due to the managers researching and trading investments to earn a better return. That means their expense ratios are likely higher than their index fund counterparts. According to the Morningstar study, the average expense ratio for active funds was .66% in 2019.