The "small" 1% fee that costs $215,000 (with JS you can run)

ghostdev — Thu, 15 Oct 2026 20:20:19 +0000

Here's a bug that doesn't throw an error, doesn't show up in any log, and quietly runs in production for 30 years.

It's the 1% fee.

You see it on a fund's page, or an advisor mentions it once, and your brain files it under "rounding error". One percent. Who cares?

Let's not argue about it. Let's run it.

The setup

Same person, same market, same discipline:

Invests $1,000 every month
For 30 years
The market returns 7% a year (a common long-run assumption after inflation, not a prediction)

The only difference: in version B, someone takes 1% a year off the top.

The code

function futureValue({ monthly, years, annualRate }) {
  const r = annualRate / 12;
  const months = years * 12;
  let balance = 0;

  for (let m = 0; m < months; m++) {
    balance = balance * (1 + r) + monthly;
  }
  return balance;
}

const usd = (x) => "$" + Math.round(x).toLocaleString("en-US");

for (const years of [10, 20, 30]) {
  const noFee  = futureValue({ monthly: 1000, years, annualRate: 0.07 });
  const oneFee = futureValue({ monthly: 1000, years, annualRate: 0.06 });

  console.log(
    `${years}y | no fee: ${usd(noFee)} | 1% fee: ${usd(oneFee)} | lost: ${usd(noFee - oneFee)}`
  );
}

Paste it into your browser console. Here's what comes out:

Years	You put in	No fee	With 1% fee	Lost to the fee
10	$120,000	$173,085	$163,879	$9,205
20	$240,000	$520,927	$462,041	$58,886
30	$360,000	$1,219,971	$1,004,515	$215,456

You contributed $360,000. The fee took $215,456. That's about 18% of your final portfolio, gone, for a number you thought was a rounding error.

Why it's so much bigger than "1%"

Because it's not 1% once. It's 1% every year, of everything, including all the growth that money would have generated.

Look at the "lost" column again: $9K → $59K → $215K. It doesn't grow linearly. The fee doesn't just take money, it takes the future compounding of that money. It's an O(n) cost in your head and something much worse in reality.

The early years look harmless, which is exactly why nobody notices until it's too late to matter.

What does "cheap" look like?

Change 0.06 to 0.069 in the code, the equivalent of a 0.1% fee, which is in the range many broad index funds charge:

futureValue({ monthly: 1000, years: 30, annualRate: 0.069 }); // ≈ $1,196,170

That costs you about $23,800 over 30 years instead of $215,000. Same market, same discipline, roughly 9x less leakage.

The 2-minute audit

If you already invest, this is a code review you can do tonight:

List everything you hold: funds, pension/retirement accounts, anything an advisor or bank set up for you.
Find the annual cost of each one. For funds it's usually called the expense ratio or TER, and it's on the fund's factsheet. Advisory or management fees are often listed separately, so add them on top.
Plug your real numbers into futureValue() and look at the "lost" column for your own timeline.

You might find everything is fine. You might find a 1.5% product you forgot you signed up for. Either way, you'll know.

The boring takeaway

You can't control what the market does next year. You can control what you pay every year. Over a long enough timeline, that's one of the few levers that reliably moves the result, and it's the one almost nobody checks.

Pick broad, low-cost funds, automate the monthly deposit, and never call sell() in a panic. Boring is the feature.

I'm a developer, not a financial advisor. This is educational content, not personalized advice. The 7% figure is a historical-style assumption, not a promise, and past returns don't guarantee future ones.

If you want to see when your own money could cover your expenses, I built a free "your number" calculator here: The Algorithm of Wealth. It's also the landing page for a short ebook I wrote on this whole system, for programmers. I also post this stuff as dev memes on Instagram, @ghostdevfinance.