Expense Ratios Explained (With Real Numbers)

Short answer: An expense ratio is the yearly fee a fund takes out of its assets, written as a percentage: 0.05% means about $5 a year for every $10,000 invested. Among the 87 S&P 500 index fund share classes in the SEC’s prospectus data (2025 Q3 to 2026 Q2), the median was 0.29%, while the cheapest open to ordinary investors cost 0.015% to 0.04%.

Every fund you’ll ever buy has a price tag, and it’s usually written as a tiny percentage: 0.03%, 0.45%, 1.12%. That number is the expense ratio. It’s the single most important cost to understand when you invest in index funds, because it’s charged every year, on everything you have in the fund, whether the market goes up or down.

This guide explains what the expense ratio includes, what it leaves out, how to read it in a real prospectus, and what it adds up to in dollars. Every example uses figures from actual fund filings with the U.S. Securities and Exchange Commission.

What an expense ratio is

The SEC’s investor education site, Investor.gov, defines it as “the percentage of a fund’s average net assets used each year to pay the fund’s operating expenses, which can include management fees, distribution and/or service fees (called 12b-1 fees), acquired fund fees and expenses, and other expenses” (Investor.gov).

In plain English: it’s the fund’s yearly running cost, expressed as a share of the money in the fund. An expense ratio of 0.50% means that, over a year, about $5 of every $1,000 invested goes to paying for the fund.

How you actually pay it

You never get a bill for the expense ratio. There’s no line on your brokerage statement that says “fund fee.” Instead, the fund takes its costs out of its own assets. As Investor.gov puts it, “funds pass along these costs to investors by deducting fees and expenses from NAV” (Investor.gov). NAV, the net asset value, is the value of the fund’s holdings per share.

That has two practical consequences:

• The returns you see are already after the expense ratio. When a fund reports its performance, the fee has already been taken out.
• You pay it in good years and bad years. The expense ratio is a percentage of your balance, not of your gains. If the fund loses money, you still pay.

What’s inside the number

Every mutual fund and ETF prospectus opens with a fee table. The expense ratio appears there as “Total annual fund operating expenses,” and it’s built from a few lines. Here’s what they mean, with real examples.

Management fee

This is what the fund’s adviser charges to run the portfolio. For big index funds it’s small, because tracking an index doesn’t require a team of stock pickers. Vanguard’s prospectus for the ETF Shares of its 500 Index Fund (VOO), for example, shows a management fee of 0.02% plus 0.01% of other expenses, for a total of 0.03%.

Distribution and service (12b-1) fees

These pay for marketing the fund and compensating the brokers and advisers who sell it. Investor.gov explains that distribution fees “cover the marketing and selling of fund shares, such as compensating brokers and others who sell fund shares” (Investor.gov). Many low-cost index funds charge none. Others charge 0.25% or even 1.00% a year.

Other expenses

Administration, custody, legal, accounting, printing and mailing, and sometimes shareholder-service fees. These can be close to zero for a giant fund and much higher for a small one.

Acquired fund fees and expenses

If a fund invests in other funds, their costs show up on a separate line. A plain index fund that owns stocks directly usually has none.

Putting it together: two real fee tables

Here’s how the lines add up for two share classes of index funds that both track the S&P 500:

Fee table line	Invesco S&P 500 Index Fund, Class A	JPMorgan Equity Index Fund, Class R6
Management fee	0.11%	0.040%
12b-1 fee	0.25%	None
Other expenses	0.18%	0.080%
Total annual fund operating expenses	0.54%	0.120%
Fee waiver	None	(0.075%)
Total after fee waiver	0.54%	0.045%

Sources: the funds’ prospectuses dated December 19, 2025 (Invesco) and November 1, 2025 (JPMorgan), as filed with the SEC.

Notice the last two lines on the JPMorgan side. That brings us to the next point.

Gross vs. net expense ratio

Some fund companies agree to waive part of their fees or reimburse some expenses for a set period, usually under a written contract. When that happens, the fee table shows two figures:

• Gross expense ratio: the total before the waiver.
• Net expense ratio: what you actually pay after the waiver.

The net figure is what matters today, but check the footnote for the end date. JPMorgan’s prospectus says the waiver on its Equity Index Fund runs until October 31, 2026. If a waiver isn’t renewed, the fund’s cost goes up to the gross figure.

What the expense ratio doesn’t include

This is where many investors get caught out. The expense ratio covers the fund’s operating costs, but several other costs sit outside it:

• Sales charges (loads). A front-end load is taken from your money when you buy, and a deferred sales charge when you sell early. Neither is in the expense ratio. A 5.75% front-end load on a $10,000 purchase means $575 goes to the sales charge before anything is invested.
• Account fees. Some fund companies charge a flat yearly fee on certain accounts. Vanguard’s 500 Index Fund prospectus, for example, lists a $25 annual account fee that can apply to some accounts.
• Trading costs inside the fund. When a fund buys and sells stocks, it pays commissions and other transaction costs. Fidelity’s prospectus for its 500 Index Fund spells this out: “These costs, which are not reflected in annual operating expenses or in the example, affect the fund’s performance.” For that fund, portfolio turnover was 3% in the most recent fiscal year, which is typical of an index fund that rarely needs to trade. Actively managed funds often trade far more.
• Brokerage commissions and bid-ask spreads you pay when buying or selling ETF shares on an exchange.
• Advisory fees. If you hold funds through a financial adviser or a managed account, their fee is charged on top of the funds’ own expense ratios.

The expense example: the most useful table nobody reads

Right below the fee table, every prospectus includes an “Example” that turns the expense ratio into dollars. Fidelity’s version introduces it like this: “Let’s say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table.” The table then shows what you’d pay in total over 1, 3, 5 and 10 years on a $10,000 investment.

Because every fund uses the same standard assumptions, the example is a fair way to compare funds. Here’s what it shows for several funds that all track the S&P 500:

Fund and share class	Expense ratio	Total cost over 10 years on $10,000
Fidelity 500 Index Fund (FXAIX)	0.015%	$19
Vanguard 500 Index Fund, Admiral Shares (VFIAX)	0.04%	$51
Invesco S&P 500 Index Fund, Class R6	0.19%	$243
Invesco S&P 500 Index Fund, Class Y	0.29%	$368
Invesco S&P 500 Index Fund, Class A	0.54% + 5.50% load	$1,190
Invesco S&P 500 Index Fund, Class C	1.29%	$1,350

Sources: each fund’s prospectus expense example, as filed with the SEC and captured in the SEC’s Mutual Fund Prospectus Risk/Return Summary data set.

The Class A figure includes the sales charge, which is why it’s so high even though its expense ratio is lower than Class C’s. The two most expensive rows cost more than 60 times as much as the cheapest one, for the same index.

Doing the math yourself

You don’t need a calculator to get a feel for it. Move the decimal point: an expense ratio of 0.03% costs about $3 a year per $10,000 invested, 0.50% costs about $50, and 1.00% costs about $100.

The real damage comes from compounding. Money paid in fees doesn’t just disappear once; it also stops growing for the rest of the time you’re invested. Investor.gov puts it simply: “Even small differences in fees can mean large differences in returns over time.”

In our analysis of S&P 500 index fund fees, we ran a hypothetical example: $10,000 invested for 30 years at 7% a year before costs. At a 0.015% expense ratio it grows to about $75,800. At 1.29% it grows to about $52,900. Same index, same starting amount, roughly $22,900 apart. (The 7% is an assumption for illustration, not a forecast.)

Do ETFs have expense ratios too?

Yes. An ETF’s expense ratio works the same way as a mutual fund’s: it’s taken from the fund’s assets and shows up in the fee table of its prospectus. The main difference is what surrounds it. ETFs don’t have multiple share classes with different fees, and the three large S&P 500 ETFs in our fee analysis (IVV, VOO and SPYM) show no 12b-1 fee at all. On the other hand, buying and selling ETF shares on an exchange can add costs that sit outside the expense ratio, like a bid-ask spread. Our comparison of index mutual funds and ETFs goes through those trade-offs.

Expense ratio vs. what you actually lose to the index

The expense ratio is the biggest reason an index fund trails its index, but it isn’t the only one. Trading costs, the small amount of cash a fund holds, the way it handles index changes and income from securities lending can all push its return a little above or below the index minus the fee. The gap between a fund’s return and its index’s return is called tracking difference. For large, cheap index funds it usually sits close to the expense ratio, which is why the expense ratio remains the best single number to compare. We’ll look at tracking difference with real filing data in a separate article.

What counts as a “good” expense ratio for an index fund?

There isn’t an official line, and it depends on what the fund tracks. Funds that follow narrow or hard-to-trade markets naturally cost more to run than funds that track large U.S. companies.

For the most common index, the S&P 500, the filings give a clear picture. Across the 87 S&P 500 index fund share classes we reviewed, the median expense ratio was 0.29%, but the cheapest classes open to ordinary investors cost between 0.015% and 0.04% (see our FXAIX vs VOO vs SWPPX comparison). In other words, for a plain S&P 500 fund, a few hundredths of a percent is achievable, and anything much above 0.10% deserves a second look.

A higher expense ratio doesn’t buy a better S&P 500 index fund. Every fund in that group is trying to deliver the same return from the same stocks. The only thing the extra cost changes is how much of that return reaches you.

Where to find a fund’s expense ratio

1. The summary prospectus. It’s usually the first document on the fund’s web page, and the fee table is on the first page or two. Look for “Annual Fund Operating Expenses.”
2. SEC EDGAR. Every prospectus is filed publicly and free to read on the SEC’s EDGAR database.
3. Your broker’s fund page. Convenient, but check the date: fees change, and a broker’s page can lag behind a new prospectus.

When you compare funds, make sure you’re looking at the same share class, the net figure, and a prospectus that’s still current.

Common misunderstandings

• “It’s such a small number, it can’t matter.” It’s small in a single year. Over decades, as the example above shows, it can add up to a meaningful share of your money.
• “I only pay it when the fund makes money.” No. It’s charged on your balance, every year, in rising and falling markets alike.
• “A fund with a higher fee must be doing more for me.” For an index fund tracking the same index, the portfolios are essentially the same. The difference usually pays for how the fund is sold, not how it’s run.
• “The expense ratio is my total cost.” Not always. Loads, account fees, trading costs inside the fund and any adviser fee sit outside it.

The bottom line

The expense ratio is the yearly price of owning a fund, taken quietly from the fund’s assets. For index funds, where the holdings are largely set by the index, it’s one of the few things that really separates one fund from another. Look it up in the prospectus fee table, check whether a waiver is propping it up, read the expense example in dollars, and remember the costs that sit outside it.

For how IndexKite reads and counts fund filings, see our Editorial Methodology. This article is general information, not personal advice; see our Financial Disclaimer.

Try it with your own numbers

Put in what you’d invest and compare two expense ratios. The calculator shows where each fund could leave you and how much of the gap comes only from the fee. It also lives on its own page: our index fund fee calculator.

Sources

• SEC, Investor.gov, glossary: Expense Ratio and Distribution and/or Service (12b-1) Fees.
• SEC, Investor.gov, Mutual Funds: fees deducted from NAV; small fee differences over time.
• Fund prospectuses as filed with the SEC on EDGAR: Vanguard 500 Index Fund (April 28, 2026); Fidelity 500 Index Fund (April 2026); Invesco S&P 500 Index Fund (December 19, 2025); JPMorgan Equity Index Fund, Class R6 (November 1, 2025).
• SEC, Mutual Fund Prospectus Risk/Return Summary data sets, 2025 Q3 to 2026 Q2: expense examples by share class.

Sources checked on September 29, 2026.