Investment Fee Calculator
Set a starting amount, a monthly contribution and an expected return, then compare two ongoing annual fee percentages side by side — this shows what the fee difference actually costs in pounds by the end, not just in percentage points.
| Scenario A | Scenario B | |
|---|---|---|
| Final value | — | — |
| Total paid in (contributions) | — | — |
| Total growth, after fees | — | — |
| Total fees paid | — | — |
Estimate only, for comparing fee levels — not a forecast, a projection of any real account, or investment advice. It assumes the same constant gross return and a constant ongoing fee applied every month for the whole period; real investments fluctuate in value, and returns, contributions and charges can all change. This is a generic calculator: it does not model, name, recommend, or compare any specific fund, platform, pension, or provider, and nothing you enter leaves your browser.
How the comparison works
Both scenarios start from the same amount and the same monthly contribution, so the only thing that differs between them is the fee. The calculator steps through the period one month at a time: each month, the balance grows by the monthly equivalent of the annual return you entered, then that month's slice of the scenario's annual fee (annual fee ÷ 12) is deducted from the resulting balance — mirroring the way an ongoing fund or platform charge is normally taken automatically as a percentage of the value held, month by month, rather than billed separately — and finally your monthly contribution is added. Total fees paid is simply the sum of every month's deduction; final value is the balance left after the last month.
Because the fee is a percentage of a balance that itself compounds, a bigger annual fee doesn't just take a bigger monthly slice — it also shrinks the amount left to grow the following month, and that gap widens every month it continues. That's why two fee percentages that look close on paper (say 0.25% and 1%) can end up years apart in pounds once contributions and growth have compounded for a decade or two.
- Why do small fee differences add up to so much money?
- Because an ongoing fee is charged on your whole balance, not just on what you originally put in — so as the balance grows, so does the pound amount taken each year. Worse, money taken as a fee is money that then can't earn a return, so you also lose out on the growth that pound would otherwise have produced. The U.S. Securities and Exchange Commission's investor education office makes exactly this point: on a $100,000 portfolio growing 4% a year over 20 years, a 1.00% annual fee leaves the portfolio worth nearly $30,000 less than the same portfolio charged only 0.25% — and separately, the total fees paid on that 1% charge add up to almost $28,000, which itself would have earned roughly another $12,000 if it had stayed invested instead. See Sources below for the exact figures.
- Is this comparing real products or providers?
- No. Both scenarios use the same made-up starting amount, contribution and return you typed in — nothing here is tied to, or drawn from, any specific fund, platform, pension scheme or provider, and the calculator never suggests switching, transferring, or choosing one. It exists purely to show how any two fee percentages compare once compounded over time, so you can bring your own real numbers (from a fund's key information document, for example) and see what they'd mean in pounds.
- What counts as the "annual fee" here?
- Any ongoing percentage-based charge taken regularly from the value of your investment — often shown on real products as an expense ratio, an ongoing charges figure, or an annual management charge. It does not include one-off charges such as a dealing commission, a platform's fixed annual fee in pounds rather than a percentage, or exit charges, none of which this calculator models. This tool is a generic estimate, not financial advice — a regulated financial adviser can help you work out what you're actually being charged on a real account and whether it's reasonable.
FAQ
Sources
Method: month-by-month simulation. Each scenario's monthly growth rate is the entered annual return compounded to a monthly-equivalent rate; each scenario's monthly fee is its annual fee ÷ 12, deducted from the balance after that month's growth and before that month's contribution is added. This is pure arithmetic on numbers you choose — the calculator carries no real fund, fee, or return figures of its own.
- U.S. SEC Office of Investor Education and Advocacy — Investor Bulletin: How Fees and Expenses Affect Your Investment Portfolio — its worked example (a $100,000 portfolio growing 4% a year over 20 years) is the basis for the FAQ figures above: a 0.50% annual fee reduces the 20-year portfolio value by $10,000 compared with a 0.25% fee, and a 1.00% fee reduces it by nearly $30,000 compared with the same 0.25% baseline; separately, the bulletin states that the total fees paid over 20 years on a 1% charge add up to almost $28,000, and that this $28,000 would itself have earned about $12,000 more had it stayed invested. The bulletin's summary of why this happens: fee money is both taken from your balance and stops earning "any return you would have earned on that fee."