Mutual Fund Calculator

Project the growth of a mutual fund investment with regular contributions, and see how much the expense ratio quietly costs you. Final value, contributions, growth, and total fees — instantly.

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Mutual Fund Calculator

Growth after expense ratio

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Final Value
Total Contributions
Total Growth
Fees Paid (vs 0%)
Net Annual Return
Contributions vs Growth

How Expense Ratios Eat Returns

A mutual fund's expense ratio is the annual percentage it charges to manage your money. It sounds tiny — often 0.1% to 1% — but compounded over decades it can consume a surprising share of your wealth. This calculator projects your fund's growth from an initial investment plus monthly contributions, applies the expense ratio as a drag on the return, and shows how much those fees cost you versus an identical zero-fee fund.

For example, $10,000 plus $500/month for 20 years at an 8% gross return grows to roughly $300,000 at a 0% expense ratio — but a 0.5% expense ratio reduces it by tens of thousands of dollars. That's why low-cost index funds, often charging under 0.1%, have become so popular: minimizing fees is one of the few investment levers entirely within your control.

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Fees Compound Too

An expense ratio is charged every year on your whole balance, so its cost grows alongside your account — quietly compounding against you.

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Low-Cost Index Funds

Index funds often charge under 0.10%. Over decades, choosing a 0.05% fund over a 1% fund can mean six figures of extra wealth.

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Dollar-Cost Averaging

Regular monthly contributions smooth out market ups and downs and harness compounding — the engine behind long-term fund growth.

Formula & Logic

Fund fees compound against you exactly as returns compound for you, which is why an expense ratio that sounds trivial produces an enormous gap over decades. The mechanism is simple subtraction — the fee reduces your annual return — but the effect is multiplicative over time. A 0.85% actively managed fund and a 0.04% index fund differ by 0.81 percentage points a year, which over twenty years removes roughly a seventh of the ending balance. Front-end loads and 12b-1 fees compound the problem, and the evidence that higher fees buy better performance is consistently weak.

Net return = Gross return − Expense ratioFV = P × (1 + net return)^nFee cost = FV at gross return − FV at net returnLoad-adjusted starting balance = P × (1 − front load)

where:

expense ratio
annual fee as a percentage of assets, deducted automatically
load
a sales charge, front-end or back-end; index funds have none
12b-1
marketing fee bundled into the expense ratio

Assumptions: Expense ratios are deducted daily from net asset value, so you never see a bill — which is precisely why they are easy to ignore. Turnover also creates taxable distributions in a taxable account, an additional cost not captured in the expense ratio.

Step-by-Step Example: 0.85% Versus 0.04% Over 20 Years

Invest $100,000 in two funds with identical gross returns and different fees.

  • Investment$100,000
  • Gross return8%
  • Active fund0.85% expense ratio
  • Index fund0.04%
  • Term20 years
  1. Zero-fee benchmark: $100,000 × 1.08²⁰ = $466,096.
  2. Active fund net return: 8% − 0.85% = 7.15%.
  3. Active fund value: $100,000 × 1.0715²⁰ = $397,964.
  4. Index fund net return: 8% − 0.04% = 7.96%.
  5. Index fund value: $100,000 × 1.0796²⁰ = $462,655.
  6. Difference: $462,655 − $397,964 = $64,691.

ResultThe 0.81% fee difference costs $64,691 over 20 years

That is 65% of the original investment, surrendered to a fee difference of less than one percentage point. The active fund would have to beat the index by 0.81% a year, every year, merely to break even — which most do not achieve over any sustained period.

FAQ

Lower is better. Broad index funds commonly charge 0.03%–0.20%, which is excellent. Actively managed funds often charge 0.5%–1%+, which is hard to justify since most don't beat their benchmark after fees. As a rule, anything above ~0.5% deserves scrutiny.
Enormously over time. A 1% annual fee can reduce a multi-decade balance by 20% or more compared with a near-zero-fee fund, because the fee is charged every year on a growing balance. Use this calculator to see the dollar difference for your own numbers.
No. Mutual fund returns vary year to year and are never guaranteed. This calculator uses a constant assumed return for projection purposes; real returns fluctuate, can be negative in some years, and past performance doesn't predict the future. Treat the result as an estimate, not a promise.

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✔ Written & reviewed by Dr Sam — 20+ yrs in management & research leadership📅 Last updated June 2026📑 How we build & check these