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    Investing / Funds

    Mutual Fund Calculator

    What a fund position grows to after its expense ratio, and what that ratio costs over the holding period. The fee is small in any one year and large over thirty.

    Balance after fees$310,961Cost of the fee$32,818Fee as % of gain15.4%
    Balance after fees
    $310,961
    net 7.25%
    Cost of the fee
    $32,818
    Against a zero-fee fund
    Fee as % of gain
    15.4%
    Of the growth
    Effective annual
    7.50%
    Net of fees
    Fee drag by year
    What the same fund would be worth without the ratio.
    Fee drag by year
    YearWith feesWithout feesCost
    Y5$50,383$51,637$1,254
    Y10$108,346$113,669$5,324
    Y15$191,543$206,088$14,545
    Y20$310,961$343,778$32,818

    A 1% fee can take a fifth of the final balance over thirty years.

    Inspect the model
    Choose a quick result view, a scaled comparison, or the complete diagnostic set.
    Canonical equations
    The exact relationships implemented by this engine.

    r_net = r_gross − expense ratio · Deducted annually.

    FV(gross) − FV(net) · The compounded difference.

    finance methodology

    A clear path from inputs to results.

    What a fund position grows to after its expense ratio, and what that ratio costs over the holding period. The fee is small in any one year and large over thirty.

    Step-by-step methodWorked exampleAssumptions explained

    How to use

    1. Set initial investment ($).
    2. Set monthly contribution ($).
    3. Set gross return (%).
    4. Set expense ratio (%).
    5. Read the headline metrics, then check the table for the detail.

    The formula

    rnet=rgross−expenseratior_net = r_gross − expense ratio

    Reference: Net return = gross return − expense ratio, compounded annually, per the SEC Form N-1A fee disclosure.

    Worked example

    At the default inputs

    Inputs
    • Initial investment ($): 10000; Monthly contribution ($): 500; Gross return (%): 8; Expense ratio (%): 0.75; Years: 20
    Calculation path
    1. 1

      Net return → 7.25% Compound both → $32,818

    Result

    Balance after fees: $310,961 · Cost of the fee: $32,818 · Fee as % of gain: 15.4%

    Interpreting the result

    A 0.75% expense ratio turns 8.00% gross into 7.25% net, costing $32,818 over 20 years.

    Assumptions & limitations

    • The expense ratio is constant.
    • Returns are nominal and smooth.
    • No sales load, tax or platform fee.

    Frequently asked questions

    Why does a small fee cost so much?

    Because it is deducted every year and the lost growth compounds — a 1% fee can take a fifth of a thirty-year balance.

    Do index funds always win?

    Lower fees help mechanically, but the gross return still has to be competitive.

    Is the expense ratio the only cost?

    No — trading costs, sales loads and platform fees sit outside it.

    Methodology last reviewed 2026-10-22. Results are informational and not financial or engineering advice — see our disclaimer.