What the Investment Fee Impact Calculator does
This investment fee calculator shows how much ongoing fees - fund expense ratios, platform charges and advisory fees - and charges on contributions reduce a portfolio over time. Enter a starting balance, monthly contributions, a return before fees and up to six fee scenarios, and it compares the ending balance of each with a fee-free benchmark, splitting the cost into fees paid and the growth those fees would have earned.
Small percentages compound. A fee of 1% a year looks trivial against a 7% return, but over twenty years it takes a far larger share of the final balance than 1% - the page makes that visible year by year. You enter the fees; nothing about any product is looked up or assumed.
How to use it
- Enter the starting balance, what you add each month, the yearly return you expect before any fees, and the number of years.
- Add a scenario for each fee level you want to compare. Put all ongoing annual charges together in the annual fee (for example a 0.20% fund plus a 0.25% platform fee is 0.45%).
- If a product takes a percentage of each contribution, enter it as the charge on contributions.
- Compare the ending balances, the total cost against no fees, and the year-by-year chart.
Reading the results
Total cost versus no fees has two parts: the fees actually deducted, and the growth that money would have earned had it stayed invested. Over long periods the second part can rival the first.
The fee-free balance is a benchmark, not an option you can buy - every real investment has some cost. The useful comparison is between your realistic scenarios.
A fee only makes sense if what it buys - advice, a strategy, convenience - is worth more to you than its cost in the table. The calculator shows the price, not the value.
Worked example: 100,000 for 20 years: 0.1% versus 1%
Take 100,000 invested for 20 years at 7% a year before fees, with no further contributions. With no fees it would grow to 100,000 x 1.07^20 = 386,968.
With a 1% annual fee charged monthly, each year's growth factor becomes 1.07 x (1 - 0.01/12)^12 = 1.07 x 0.990046 = 1.059349, and 1.059349^20 = 3.16797, so the balance ends at 316,797. That is 70,172 less - 18.1% of the fee-free result - of which 37,725 was paid in fees and 32,447 is growth those fees would have earned.
At 0.1% a year the balance ends at 379,306, only 7,663 below the benchmark. The gap between the two fee levels is 62,509 on the same investments.
Formulas and scoring rules
- Monthly growth
r_m = (1 + annual return)^(1/12) - 1- Each month
balance = balance x (1 + r_m) + contribution x (1 - charge); then fee = balance x annual fee / 12 is deducted- Lump sum closed form
ending = start x ((1 + r_m) x (1 - fee/12))^(12 x years)Used in the tests to check the month-by-month engine.- Total cost
cost = fee-free ending - scenario ending = fees paid + growth lost- Rounding
Balances shown to the nearest whole unit; nothing is rounded in the calculation
Where investment fees hide
The ongoing charge or expense ratio of a fund is taken inside the fund, so you never see it deducted - it simply lowers the fund's return. Platform or account fees are usually a percentage of your balance. Advisers may charge a percentage too, or a fixed fee. Add all the percentage charges together for the annual fee here.
Other costs are harder to see: dealing spreads, transaction costs inside a fund, and performance fees. If a provider discloses a total cost figure, use that. The US SEC's investor education site and your provider's cost disclosure explain what each charge covers.
Limitations: what the result does not prove
- Returns are assumed constant. Real returns vary, but fees are charged whatever happens, so their relative cost is larger in poor years.
- Fixed-amount fees (a flat 100 a year, say) are not modelled; convert them to a percentage of your balance if needed.
- Taxes and inflation are not included.
- It compares costs only. It does not know what any fee buys you or recommend any product.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
- Investor.gov (US SEC) - understanding fees - checked 19 Sep 2026
- Investor.gov (US SEC) - mutual fund fees and expenses
Frequently asked questions
How much does a 1% fee cost over time?
More than 1% of your money. On 100,000 growing at 7% for 20 years, a 1% annual fee leaves you with about 18% less than no fees at all - about 70,000 - because each fee also removes the growth it would have earned.
What is an expense ratio?
It is a fund's annual running cost as a percentage of the money invested in it, deducted from the fund's assets rather than billed to you. A 0.20% expense ratio costs 2 a year for every 1,000 invested, before counting growth lost.
Should I add the platform fee to the fund fee?
Yes, if both are percentages of your balance. The calculator treats the annual fee as the total yearly percentage taken from your money, so a 0.15% fund on a 0.25% platform is 0.40% in total.
What is a front-end load or contribution charge?
It is a percentage taken from each amount you invest before it is invested. A 5% load means only 95 of every 100 you contribute starts working. Enter it as the charge on contributions; the second example compares a 5% load with none.
Why does the fee cost grow faster than the fee itself?
Two reasons: the fee is a percentage of a balance that keeps growing, and every amount taken out loses all the future growth it would have earned. Both effects compound, so the cost rises steeply in later years.
Is a higher-fee fund ever worth it?
Only if it delivers enough extra return after its fees, or a service you value, to beat the cheaper option. Past outperformance does not guarantee future results, while the fee is certain. The table shows the gap in money that the extra return would have to make up.
Last reviewed by the A2Z.Tools team against the sources listed above.
