How the mutual fund returns calculator works

Your lump sum and each monthly contribution are compounded monthly at your net return — the gross return minus the fund’s expense ratio. That fee looks tiny, but because it’s charged every year on your whole balance, it compounds against you. The calculator shows the total fee drag so you can see exactly what a half-percent really costs over a lifetime of investing.

Total invested is your initial amount plus every monthly contribution. Everything above that is your gain. For irregular contributions or withdrawals, use our XIRR Calculator; to compare against a simple lump sum, see the Lump Sum Calculator.

Why the expense ratio matters more than you think

A fund charging 1% instead of 0.05% doesn’t cost you 1% once — it costs roughly 1% of your entire balance every single year. On a portfolio that compounds for 30 years, that difference can quietly consume a fifth or more of your final wealth. This is the single strongest argument for low-cost index funds: you keep more of the market’s return instead of handing it to a manager.

• Index funds / ETFs: typically 0.03-0.20% — the low-cost default for most investors.
• Actively managed funds: often 0.5-1.0%+, and most fail to beat their index after fees.
• Rule of thumb: every 1% in annual fees is roughly a 1% cut to your long-run return.

Frequently asked questions