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Funds & ETFsExplainer

What is an expense ratio, and how much does it really cost you?

An expense ratio is the yearly cost of owning a fund, shown as a percent of assets. See what it includes, what it leaves out and its cost over 30 years.

By The Token Thesis DeskNote No. 0276 min read11 cited sources

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Quick answer

An expense ratio is the share of a fund's average net assets used each year to pay its operating expenses, such as management and 12b-1 fees. It is taken from the fund, not billed to you, and reduces your return every year you hold the fund.

Key points

  • The expense ratio is a fund's total annual operating expenses as a percentage of its average net assets.
  • You never see a bill: the cost is deducted from fund assets, so it shows up as a slightly lower return.
  • It does not include sales loads, brokerage commissions, bid-ask spreads or the fund's own trading costs.
  • At an illustrative 5% yearly return, a 1.00% ratio leaves about 25% less after 30 years than a cost-free fund; a 0.05% ratio leaves about 1.4% less.

What does an expense ratio measure?#

The SEC's Investor.gov defines the expense ratio as the percentage of a fund's average net assets used each year to pay the fund's operating expenses[1]. Those expenses can include management fees, distribution and/or service fees (called 12b-1 fees), acquired fund fees and expenses, and other expenses[1].

In a prospectus the same number appears as Total Annual Fund Operating Expenses, expressed as a percentage of average net assets[2]. FINRA describes it as the percentage of a fund's assets that goes toward its recurring fees every year[3]. Both mutual funds and ETFs have one[4].

Worked example

Worked example: from dollars to a ratio

An illustrative fund spends $1.5 million a year on operating expenses and has average net assets of $300 million. Dividing one by the other gives the ratio. The other rows turn common ratios into basis points and into a first-year dollar cost on $10,000.

CalculationResult
$1.5M expenses ÷ $300M average net assets0.50%
0.05% in basis points5 bp
0.50% in basis points50 bp
0.05% of $10,000 (first year, roughly)$5.00
0.50% of $10,000 (first year, roughly)$50.00
1.00% of $10,000 (first year, roughly)$100.00

Figures computed in code from the stated inputs; rounded to the nearest cent or tenth.

How do you actually pay it?#

You do not write a check. The fund takes the cost out of its own assets, and the SEC notes that funds pass along costs to investors by deducting fees and expenses from NAV[6]. The prospectus fee table calls these "annual fund operating expenses" — ongoing charges paid by the fund that you pay indirectly each year you are invested[7].

Because the deduction happens inside the fund, the return you see is already after the expense ratio. That makes the cost easy to overlook. Investor.gov's warning is short: even small differences in fees can mean large differences in returns over time[8].

Where the expense ratio goes

1Fund's holdingsearnDividends, interest,price change2OperatingexpensesManagement, 12b-1,other3Deducted fromNAVInside the fund4Your returnAlready net of theratio1Fund's holdings earnDividends, interest, price change2Operating expensesManagement, 12b-1, other3Deducted from NAVInside the fund4Your returnAlready net of the ratio
Expenses come out of fund assets before anything reaches your account value.

What does the expense ratio leave out?#

The ratio covers the yearly running costs only. Other costs sit outside it, and some are charged directly to you as shareholder fees[2].

Costs inside and outside the expense ratio
CostIn the expense ratio?Where to find it
Management feeYesProspectus fee table
12b-1 (distribution/service) feeYes — capped at 1% of your assets in the fundProspectus fee table
Front-end or deferred sales loadNo — charged to you when buying or sellingShareholder fees section
Fund's own trading (turnover) costsNo — but they still reduce performancePortfolio turnover section
Brokerage commission and bid-ask spreadNo — paid each time you tradeYour broker; the ETF's website

Fee table lines and turnover costs: Form N-1A[9]. 12b-1 cap: FINRA[3]. Loads: SEC fee bulletin[2]. ETF trading costs: FINRA[4].

Form N-1A, the SEC form funds use for their prospectus, makes the turnover point explicit: a fund pays transaction costs such as commissions when it buys and sells securities, and these costs are not reflected in annual fund operating expenses but still affect performance[9]. For a wider view of costs, see how investment fees affect returns.

How much does a small ratio add up to over time?#

Form N-1A's standard cost example assumes a 5% return each year[9]. Using that same illustrative 5%, the table below compares $10,000 held with no costs against three expense ratios. The model is simple: each year's net return is 5% minus the ratio. It is not a forecast — real returns vary and can be negative.

$10,000 at an illustrative 5% a year before costs
Expense ratioAfter 10 yearsGap vs no cost (10 yrs)After 30 yearsGap vs no cost (30 yrs)
No cost (reference)$16,288.95—$43,219.42—
0.05% a year$16,211.55$77.40$42,606.25$613.18 (1.4%)
0.50% a year$15,529.69$759.25$37,453.18$5,766.24 (13.3%)
1.00% a year$14,802.44$1,486.50$32,433.98$10,785.45 (25.0%)

Calculated in code with balance = 10,000 × (1.05 − ratio)^years. Illustrative rate, not a forecast.

$10,000 at 5% a year: 0.05% vs 1.00% expense ratio

$0$12k$25k$38k$50k051015202530Years$0$12k$25k$38k$50k051015202530Years
0.05% expense ratio1.00% expense ratio
Same starting amount and same return before costs. The gap is the compounding cost of the higher ratio.

The SEC's own fee bulletin reaches the same conclusion with different inputs: $100,000 growing 4% a year for 20 years ends at roughly $208,000 with a 0.25% yearly fee but roughly $179,000 with a 1.00% fee[10]. Try your own numbers in the fee drag calculator.

How do you compare expense ratios fairly?#

  1. Find the fee table

    Open the prospectus or summary prospectus and find Total Annual Fund Operating Expenses near the front[2]. Our prospectus guide shows where.

  2. Match the share class

    The same fund can have different expenses in different share classes; FINRA's Fund Analyzer compares funds and share classes[3].

  3. Compare like with like

    A broad index fund and a specialised active fund do different jobs. Compare costs among funds with a similar strategy.

  4. Add the costs outside the ratio

    Check loads, any account fees, and for ETFs the bid-ask spread and commissions you will pay to trade.

What mistakes do beginners make?#

  1. Treating 1% as "almost nothing"

    In the table above, 1.00% a year costs about a quarter of the cost-free ending balance after 30 years at a 5% illustrative return.

  2. Comparing the wrong share class

    Class A, B or C shares of the same portfolio can carry different ratios. Use the ratio for the class you would actually buy.

  3. Forgetting loads and trading costs

    A 5% front-end load takes $500 of a $10,000 purchase before anything is invested[2] — five times the first-year cost of a 1.00% expense ratio on the same amount. Spreads and commissions add up the same way for frequent traders.

What else do beginners ask?#

Where do I find a fund's expense ratio?

In the prospectus fee table[1], shown as Total Annual Fund Operating Expenses[2].

Do ETFs have expense ratios?

Yes. FINRA notes that exchange-traded products have expense ratios like mutual funds, but no loads or 12b-1 fees[4].

Is the expense ratio charged even if the fund loses money?

Yes. The SEC's guide notes that fund investors pay fees and expenses regardless of how the fund performs[11].

Can a fund's expense ratio change?

Yes. The ratio is a percentage of average net assets and the expenses behind it can change, so check the latest prospectus rather than an old figure.

What is the bottom line?#

The expense ratio is a fund's yearly running cost, taken quietly from its assets. It does not cover loads, trading costs or spreads, so it is only part of what you pay — but because it repeats every year, it compounds. Find it in the fee table, compare it among similar funds and share classes, and add the costs it leaves out.

Sources

Numbers in brackets in the text point here. Grade A = primary source (regulator, statistics agency, law or official document).

  1. 1
    Expense Ratio (glossary)U.S. SEC — Investor.gov (n.d.) · Grade A
  2. 2
    Mutual Fund and ETF Fees and Expenses – Investor BulletinU.S. SEC — Investor.gov (2025) · Grade A
  3. 3
    Mutual FundsFINRA (n.d.) · Grade A
  4. 4
    Exchange-Traded Funds and ProductsFINRA (n.d.) · Grade A
  5. 5
    Basis Point (glossary)U.S. SEC — Investor.gov (n.d.) · Grade A
  6. 6
    Exchange-Traded Funds (ETFs)U.S. SEC — Investor.gov (n.d.) · Grade A
  7. 7
  8. 8
    Mutual FundsU.S. SEC — Investor.gov (n.d.) · Grade A
  9. 9
    Form N-1A (registration form for open-end funds, instructions)U.S. Securities and Exchange Commission (n.d.) · Grade A
  10. 10
  11. 11
    Mutual Funds and ETFs: A Guide for InvestorsU.S. Securities and Exchange Commission (2016) · Grade A

How we checked this note

Every number, date and rule above links to its source. This note cites 11 sources, 11 of them primary (Grade A). Worked examples were calculated in code, and a second editor compared each figure with its source before publishing. Spotted an error? Tell us — corrections are listed on the note. Read our editorial policy.