Taxes, Fees, and Realistic Returns

Keep projections honest without turning the tool into a tax engine

This calculator projects a clean 8% with no fund expenses, no advisor fee, and no tax bill. Your actual account will have at least one of those. The fix is not a more complicated tool — it is a slightly lower number in the return field.

Subtract your costs from the return

Find the expense ratio of your funds. A broad index fund might charge 0.03% to 0.10%; an actively managed fund might charge 0.50% to 1.00%.

If you pay an advisor, add their fee too. A common arrangement is around 1% of assets per year.

Then subtract the total from your assumed return. An 8% expectation with a 0.05% index fund is effectively 7.95%, which barely matters. The same 8% with a 1% fund plus a 1% advisor is 6%, which matters enormously.

Key points

Index fund only: subtract roughly 0.05% — close enough to ignore.
Actively managed funds: subtract 0.50% to 1.00%.
Advisor on top: subtract another 1.00% or so.
Two percent of total drag over 30 years can cost a third of your ending balance.

Taxes depend on the account, not the investment

Money inside a 401(k) or traditional IRA grows untaxed until you withdraw it, so you can model it at the full return and remember that withdrawals will be taxed as income.

Money inside a Roth account grows and comes out tax-free if you follow the rules, so the projection is closest to reality there.

Money in a regular brokerage account gets taxed on dividends each year and on gains when you sell. Shaving roughly half a point off the return is a rough but workable adjustment.

Key takeaway Fees and taxes are not a footnote — they are a permanent subtraction from your return. Run the projection at a rate that already has them removed, and the number you see is the one you might actually keep.

Why a small percentage becomes a large number

A 1% fee sounds trivial next to an 8% return, and that framing is exactly why fees survive. The fee is not charged once — it is charged every year on the entire balance, including the growth that the fee already reduced in prior years.

Picture a $300,000 balance. A 1% annual fee is $3,000 that year, and it is $3,000 that will never compound for you again. Repeat that across thirty years, on a balance that keeps growing, and the cumulative cost climbs into six figures on plans of that size.

This is why the difference between a 0.04% index fund and a 0.85% actively managed fund is not a rounding error. Over a full career it is frequently the difference between retiring on schedule and working several more years.

Run the honest version

Take whatever scenario you already built and rerun it twice: once at your headline rate and once at that rate minus your total drag.

The difference between the two is what fees and taxes cost you over the full horizon. For long timelines it is usually a startling number, and it is the strongest argument there is for choosing low-cost funds.

You do not need to model this perfectly. Getting within half a percent is enough to make good decisions.

                    Worth checking today: log into your retirement account and look up the expense ratio on each fund you own. It takes ten minutes and is the highest-return chore in personal finance.
                

Try these inputs

Headline: $10,000 start, $400/mo, 8%, 30 years
After a low-cost index fund: same inputs at 7.9%
After 1% funds plus a 1% advisor: same inputs at 6%

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