The expense ratio is the annual fee a mutual fund or ETF charges to manage your money, taken straight out of your returns before you ever see a statement. At 0.04% it sounds like rounding error; at 0.50% it still sounds small. But over 30 years of compounding, a fraction of a percent per year grows into one of the largest single leaks in a retirement portfolio. This expense ratio calculator puts two funds side by side — one low-cost index fund and one higher-cost fund — and shows you exactly what that fee difference costs in dollars at the end of your horizon.
Type in your starting balance, the two expense ratios you are comparing, an assumed gross annual return, and the number of years until you withdraw. Every figure updates instantly, so you can stress-test what happens at 1%, 2%, or 30 years instead of only at the 30-year default.
How to Use
- Enter the Initial Investment — the lump sum going into the account today. For many people this is a current 401(k) balance, an IRA rollover, or a starting brokerage deposit.
- Set the Low-Cost Fund Expense Ratio. A broad-market index ETF typically charges 0.03%–0.10% per year; the default 0.04% mirrors popular S&P 500 index funds.
- Set the High-Cost Fund Expense Ratio. A typical actively managed mutual fund charges 0.50%–1.00% per year; 0.50% is a fair middle-of-the-road default.
- Pick a realistic Gross Annual Return before fees. The long-run US stock market averages roughly 7% after inflation, before fees — use 10% if you prefer nominal pre-inflation figures.
- Choose your Investment Horizon. Ten years barely reveals the drag; thirty years makes it obvious.
- Read the result card: ending balances for both funds, the dollar difference (the fee drag), the yearly fee charged on day one, the fee charged at the end of the horizon, and the drag expressed as a percentage of the final balance.
How Expense Ratios Drag Down Your Balance
The math is straightforward compound growth with one small subtraction each year. If a fund's gross return is 7% and its expense ratio is 0.50%, your money actually grows at 6.50%. The formula the engine uses is:
Ending balance = Principal × (1 + gross return − expense ratio)ⁿ
where n is the number of years. On a $100,000 investment at 7% gross for 30 years:
- A 0.04% fund compounds at 6.96% and ends near $752,735.
- A 0.50% fund compounds at 6.50% and ends near $661,437.
- The gap — $91,298 — is money that never reached your account.
That is 12.13% of what the low-cost investor ends up with. Notice the yearly fee in dollars is not the headline number: on day one, the difference is only $46 ($500 vs $40). It grows because the fee is charged on a larger and larger balance. By year thirty, the high-cost fund alone charges roughly $3,307 in a single year, while the index fund charges about $301 on a balance that is itself higher.
Examples
Example 1 — The classic comparison. A saver puts $100,000 into a 0.04% S&P 500 index fund and a friend puts the same $100,000 into a 0.50% actively managed fund. Both average 7% gross for 30 years. The index account grows to about $752,735; the active account to about $661,437. The 0.46% annual difference has quietly cost the active investor $91,298 — close to one full year of starting salary gone in fees.
Example 2 — A shorter horizon. Over just 10 years at the same 7% gross, the same 0.04% vs 0.50% comparison produces an ending difference of only about $8,267 (roughly $195,981 vs $187,714). Fees still matter, but compounding has not had time to magnify them. This is why fee sensitivity rises with age: a 25-year-old should treat expense ratios as a first-order decision; a 62-year-old already in withdrawal has less compounding left to lose.
Example 3 — A seven-figure balance. On a $1,000,000 portfolio, the identical 0.04% vs 0.50% gap over 30 years grows to about $912,979 — the low-cost account reaches roughly $7.53 million versus $6.61 million. At scale, switching one 0.50% fund for a 0.04% index fund is worth more than most people's entire annual salary, every single year of the holding period.
FAQ
What is a good expense ratio for an ETF?
For a broad-market US stock ETF, anything under 0.10% is excellent, and the largest S&P 500 index funds now charge 0.03%–0.04%. For bond index ETFs, 0.05%–0.10% is typical. Anything above 0.20% for a plain index exposure is worth shopping around, and anything above 0.50% should have a very specific reason behind it.
How much difference does 0.50% expense ratio actually make?
On a $100,000 portfolio averaging 7% gross over 30 years, a 0.50% fund ends around $661,437 versus $752,735 in a 0.04% fund — a difference of about $91,298, or roughly 12% of the final balance. Even 0.50% versus 0.25% would cost tens of thousands of dollars over the same horizon.
Are expense ratios charged on every dollar I invest?
Yes. The fee is deducted proportionally every day from the fund's net asset value; you never see a bill. On a $100,000 balance, a 0.50% ratio means $500 is quietly removed in year one, and as the balance grows that yearly dollar figure grows with it — which is why small percentage differences become huge dollar differences over decades.
Do high-cost funds beat low-cost funds enough to justify the fee?
The evidence is weak. Studies from S&P Dow Jones Indices (the SPIVA reports) show that the large majority of actively managed funds underperform their benchmark over 5- and 10-year periods, and the hurdle is mathematically unfair: a fund charging 0.50% must beat its benchmark by 0.50% every single year just to tie it after fees. Past performance does not guarantee future results, but the fee hurdle is guaranteed.
What other fees should I watch besides the expense ratio?
Look at transaction costs (turnover), front-end or back-end loads, 12b-1 marketing fees (often hidden inside the expense ratio), expense waivers that expire, and advisory fees layered on top of the fund itself. A fund with a 0.50% expense ratio plus a 1.00% advisor fee is a 1.50% annual drag — use this calculator twice and add the two gaps together.
Should I switch funds just to lower my expense ratio?
Usually yes, but check first: selling may trigger capital-gains taxes in a taxable account, surrender charges in an old annuity, or exit fees. In a tax-advantaged account (401(k), IRA, Roth IRA) there is no tax cost at all, so rolling a 0.75% fund into a 0.05% index option is almost free money. Run your own numbers above before deciding.
Disclaimer
This expense ratio calculator is provided for informational purposes only and does not constitute investment, tax, or financial advice. All projections are based on the inputs you enter and a simplified compound-growth model that deducts the expense ratio from a constant assumed gross return; actual fund returns vary by year, may be negative, and do not include taxes, inflation, trading costs, loads, or advisory fees. Past market averages do not guarantee future results. Always confirm the actual expense ratio in the fund's prospectus or annual report, and consult a qualified financial professional before moving money.