Expense Ratio Calculator
A Small Percentage That Compounds Against You
A fund's expense ratio looks small on paper — often well under 1% — which is exactly why it's easy to underweight when choosing between funds. But a fee is subtracted every year, which means it compounds against your balance the same way a return compounds in your favor. Over a multi-decade holding period, the gap between a low-cost and a high-cost fund tracking the same index can add up to a substantial fraction of the total account value.
The Formula
Value without fee = Investment × (1 + Return / 100)Years
Total Cost of Fees = Value without fee − Value with fee
The expense ratio is treated as a direct annual drag on the return rate, then compounded over the holding period exactly as the return itself would be — which is what makes its long-run cost larger than the simple annual percentage suggests.
Where This Matters
- Choosing between similar index funds — two funds tracking the same index with different expense ratios will diverge in value over time purely due to the fee, since their gross returns are close to identical.
- Retirement account fund selection — 401(k) plans often carry higher-cost fund options alongside cheaper ones tracking similar benchmarks; the long time horizon of retirement savings magnifies the fee's impact.
- Evaluating actively managed funds — a higher expense ratio needs to be justified by outperformance large enough to offset the compounding fee drag shown here, not just a marginally better track record.
Worked Example
| Expense ratio | Value after 20 years | Total cost of fees |
|---|---|---|
| 0.05% (typical index fund) | $191,683.96 | $1,800.26 |
| 0.75% (typical active fund) | $168,092.67 | $25,391.55 |
Both scenarios start from the same $193,484.22 fee-free value; the difference in expense ratio alone accounts for over $23,000 of the gap between them.
How to Use This Calculator
- Enter the amount invested.
- Enter the fund's expense ratio as a percentage.
- Enter the expected annual return before fees.
- Enter the number of years you plan to hold the investment.
- Select Calculate to see the first-year fee, the value with and without the fee applied, and the total cost of fees over the period.
Related Calculations
Compare the long-run effect of that fee drag to compounding gains using the Future Value Calculator, or see the Dollar Cost Averaging Calculator for how regular contributions interact with fund costs over time.