ProofOfReturns
Tool 01

Fee drag calculator

What a fund's yearly charge costs you in euros: the charge itself, and the growth that money would have made if it had stayed invested.

After 20 years, fund B leaves you €4,075 more than fund A.

You end withPaid in chargesGrowth the charges never made
Fund A 1.28% €16,934€3,459€1,518
Fund B 0.21% €21,009€636€266
No charge at all€21,911——

Where it bends. Both funds get the same return before costs, so the gap is the cost alone; whether a dearer fund earns more is a separate question this tool does not answer. Every year gets the same return; real years are uneven, so read the result as the size of the cost, not as a forecast of your balance. It counts ongoing charges only: no entry or exit fees, trading costs, what your broker or platform charges, tax or inflation. The two default charges are EU averages; your own fund's charge is in the document your provider gives you before you buy. Educational, never advice.
01 Under the hood

How the tool works it out

Year by year, the tool does three things. Any yearly addition goes in at the start of the year. The whole amount then grows by the return you entered. At the end of the year the charge comes off, as a percentage of what is there. It does this for fund A, for fund B, and once with no charge at all.

Each year amount = (amount + yearly addition) × (1 + return)
charge = amount × yearly cost
amount = amount − charge

Then it splits what you lose into two parts, the way the American markets regulator does: you lose the charge, and you lose the return that the charge would have earned.1 Paid in charges is all the yearly charges added up. Growth the charges never made is what is left of the gap with the no-charge amount once those charges are taken out.

As a test, the tool reproduces that regulator's own worked example: $100,000, a charge of 1% a year and an assumed 4% return, held for twenty years. The tool gives $27,832 in charges and $12,067 in growth those charges never made; the regulator writes "almost $28,000" and "an additional $12,000".1

The numbers that go in

NumberWhat it isWhere it comes from
1.28%default yearly cost, fund AAverage ongoing costs of actively managed equity funds in the EU in 2024, from the European markets regulator.2 An average across funds for private and professional investors together.
0.21%default yearly cost, fund BAverage ongoing costs of equity ETFs in the EU in 2024, from the same table, so the two defaults are comparable.2
4%default return before costsOur choice, borrowed from the American regulator's worked example. It is an assumption, not a forecast and not a measurement. Change it; the tool takes 0% to 15%.
€10,000 · 20 yearsdefault amount and periodOur choice. €10,000 is the amount the European regulator uses in its own worked case;2 twenty years is the period in the American example.1
start of the yearwhen a yearly addition goes inOur choice.
once a yearwhen the charge comes offOur choice: with it, the tool reproduces the regulator's worked example.

Why the euro figure your provider sends still does not answer the question you have — read the explainer on fees in euros.

Sources

  1. U.S. Securities and Exchange Commission, Office of Investor Education and Advocacy, Investor Bulletin: How Fees and Expenses Affect Your Investment Portfolio, Pub. No. 164 (2014). Our source for: the mechanism — you also lose the return the charge would have earned (p. 3) — and the $100,000 / 4% / twenty-year worked example (p. 3).
  2. European Securities and Markets Authority, Costs and Performance of EU Retail Investment Products 2025, ESMA50-1949966494-4065 (cover date 3 March 2026; reporting period 1 January 2015 – 31 December 2024). Our source for: average ongoing costs of actively managed equity funds and of equity ETFs in 2024 (p. 18), and the €10,000 worked case (p. 6).

How we checked. Verified 16 October 2026. The split into two parts and the worked example come from source 1, page 3; the order of the yearly steps is ours, and with it the tool reproduces that example. The two default charges come from source 2, page 18; both were read out of the report twice, independently, for our explainer on fees in euros, and the two readings agreed. The tool's own code is tested against a second, separate implementation of the same sums, on nine cases: the regulator's example, the defaults, a case with yearly additions, a single year, a fund B that costs more than fund A, two funds that cost the same, and three inputs outside the range. The numbers marked as ours are choices, not measurements. Think we got something wrong? Tell us at info@proofofreturns.com. We correct in public.