Comprehensive Guide
Learn more in our Investing Guide.
How it works
An expense ratio looks harmless because it is quoted as a small annual percentage — but it is charged on the whole balance every single year, and every dollar taken in fees is a dollar that stops compounding for every year that follows. That is why a 1% fee does not cost 1% of the result: over a long horizon it routinely consumes 15-25% of the final balance. The calculator runs two identical investments side by side — one compounding at the full pre-fee return (a near-zero-cost index fund), one at the return minus your fund's expense ratio — and shows both ending balances, the dollar gap between them, and that gap as a share of the final balance. The gap widens fastest in the last decade, because fees scale with the balance and the balance is biggest at the end. The practical use is comparison shopping: run your current fund's expense ratio, then run 0.05% for a broad index fund, and the difference between the two results is the pay rise you give yourself by switching — taken with no extra risk, since the fee is the one input in investing that is both certain and entirely under your control.Formula
Cost = FV at gross return - FV at (gross return - expense ratio), same contributions
Tips
- A 1% fee costs far more than 1% of the result — the drag compounds with the balance.
- Fees are charged on the whole balance yearly, so the cost grows as you do.
- Dropping from 1.00% to 0.05% is a pay rise with no extra risk.
- Compare the dollar gap, not the percentage — it is the number that funds retirement.
- Fee is the only certain input in investing: returns vary, the fee does not.