About the Expense Ratio Calculator
This expense ratio calculator compares two mutual funds or ETFs that earn the same market return but charge different annual fees. Enter your starting investment, any monthly contributions, the expected return before fees, both expense ratios and how long you will stay invested. It shows the ending balance for each fund, how much each loses to fees compared with a no-fee benchmark, and the dollar gap between them.
It is useful when choosing between an index fund and an actively managed fund, reviewing the funds in a 401(k) or IRA menu, or deciding whether to switch out of an expensive fund. A difference that looks tiny as a percentage — say 0.03% versus 1% — compounds into a large amount of money over decades because the fee is charged on your whole balance every year, including past growth.
The model subtracts each expense ratio from the gross return and compounds monthly, with contributions added at the end of each month. It does not include sales loads, trading costs or taxes, which would widen the gap further for most high-cost funds.
With the default inputs, the extra cost of the higher-fee fund is $272,189.70. Change any value above to recalculate instantly.
How to use the expense ratio calculator
- 1Enter your starting balance and any monthly contribution.
- 2Enter a realistic annual return before fees (for example 6–8% for a stock-heavy portfolio).
- 3Enter the expense ratios of the two funds you are comparing, found on each fund’s fact sheet.
- 4Choose how many years you expect to stay invested.
- 5Compare the ending balances and the dollar cost of the higher fee.
Formula and method
Each fund’s balance grows at its net return: the gross annual return R minus its expense ratio ER. The net rate is compounded monthly over t years on the initial investment P, and each monthly contribution C is added at the end of the month and compounds from then on.
The cost of fees is measured two ways: the gap between the two funds, and each fund’s shortfall against a no-fee benchmark earning the full return R. Because the expense ratio is charged on the entire balance every year — including earlier gains — the dollar cost grows much faster than the percentage suggests.
- P
- Initial investment
- C
- Monthly contribution
- R
- Annual return before fees
- ER
- Expense ratio (annual fee as % of assets)
- t
- Years invested
Worked examples
$100,000 for 30 years: 0.03% index fund vs 1% active fund
At 8% before fees, compounded monthly, the 0.03% fund grows to about $1.084M while the 1% fund reaches about $812K. The higher fee costs roughly $272,000 — more than 2.7 times the original investment — even though it is under 1 percentage point a year.
$500 a month for 25 years: 0.10% vs 0.75%
Investing $500 a month ($150,000 in total) at a 7% gross return grows to about $398,684 in the 0.10% fund but only about $360,137 in the 0.75% fund. The 0.65-point fee gap costs about $38,547.
Frequently asked questions
What is a good expense ratio?+
Broad index funds and ETFs commonly charge 0.02–0.20% a year. Actively managed stock funds often charge 0.5–1% or more. Lower is generally better because fees are certain while outperformance is not.
How is the expense ratio charged?+
You never receive a bill. The fund deducts its fee from assets a little at a time, so the fund’s published returns are already net of the expense ratio. That is why the cost is easy to overlook.
Does a 1% fee really matter?+
Yes. Over 30 years at an 8% gross return, a 1% annual fee reduces the ending balance by roughly a quarter compared with a near-zero-fee fund, because the fee compounds against you along with your returns.
Where do I find a fund’s expense ratio?+
It is listed in the fund’s prospectus and fact sheet, and on most broker and fund-company websites. Look for the net expense ratio, which reflects any fee waivers currently in place.
Are there other fund costs besides the expense ratio?+
Some funds charge sales loads, 12b-1 marketing fees (usually included in the expense ratio), redemption fees and account fees, and all funds incur trading costs. Financial advisers may add an advisory fee on top.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.