Mutual Fund Calculator
Adjust the inputs below. Results update as you type.
How it works
Net annual return = gross return − expense ratio. A 1% expense ratio on a $100,000 portfolio costs $1,000/year and compounds: over 30 years at 7% gross, a 1% fee reduces the final balance by ~25% compared to a 0.05% index fund. Load funds charge a sales commission (front-end or back-end) on top of the expense ratio. FINRA's fund analyzer compares total costs.
Input guidance
- Use realistic rates from lender or provider quotes instead of headline averages.
- Model conservative, baseline, and optimistic scenarios before deciding.
- Include recurring real-world costs (fees, taxes, insurance, maintenance) where relevant.
The formula
Fund value grows with returns net of fees: FV = P·(1 + r − fee)^n plus the future value of contributions. The expense ratio is subtracted from the gross return each year.
Worked example
$20,000 plus $200/month at an 8% gross return with a 0.5% expense ratio (net 7.5%) over 25 years grows to roughly $290,000; a 1.5% fee would cut tens of thousands from that.
More examples to test
- Conservative case: use a higher interest rate and lower growth assumptions to stress-test affordability.
- Optimistic case: use a lower rate with stable income assumptions to compare upside potential.
How to interpret results
Treat this as a planning model, not a final approval tool. Compare at least two scenarios and focus on total-cost and cash-flow trade-offs.
When this can be inaccurate
Results can diverge due to fees, changing rates, tax rules, lender policies, and behavior changes that simplified models cannot fully capture.
Change history
- July 2026: Quality-reviewed for publication with formula checks and explanatory copy updates.
Site-wide corrections also appear on the corrections log.
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Frequently asked questions
What is an expense ratio?+
The annual percentage a fund charges to manage your money. Even small differences compound into large sums over decades.
Are returns guaranteed?+
No. Mutual funds rise and fall with their holdings. Past performance does not predict future results; this is a planning projection only.
Why do fees matter so much?+
Fees are charged on your whole balance every year and compound against you, so low-cost index funds often outperform pricier active funds over time.
How should I use this result?+
Treat it as a planning estimate. Compare at least two realistic scenarios, then confirm with statements, quotes, or a qualified professional before acting.
How often should I refresh assumptions?+
Refresh whenever rates, income, costs, or policy limits change materially, and before making irreversible commitments.