Fund Fee Calculator (UK): what an OCF costs over time
Put two fund fees side by side on the same contributions and the same assumed return, and see how far apart the two pots end up. Results update instantly, the formula is shown with your numbers, and the chart draws both pots year by year. No sign-up.
- Final value at fee A£0
- Final value at fee B£0
- Total fees paid at fee A£0
- Total fees paid at fee B£0
- Total you contribute£0
Fee A vs fee B, year by year
Green = the pot at fee A. Amber dashed = the pot at fee B. The gap between the lines is the fee difference compounding.
Quick answer
Starting with £10,000 and adding £300 a month for 25 years at an assumed 6% gross return, a 0.07% fee leaves £249,552 and a 0.22% fee leaves £243,271 — a difference of £6,281. An illustration on an assumed constant return, not a forecast. Change the inputs above and this answer updates.
The same plan over different horizons
Everything else as entered above; your own horizon is highlighted.
| Horizon | At fee A | At fee B | Difference |
|---|
What an ongoing charge is
Most funds publish an ongoing charges figure (OCF): the yearly cost of running the fund, expressed as a percentage of the money you hold in it. You never receive a bill for it. It is taken from inside the fund, so the only place it shows up is in a return that is slightly lower than it would otherwise have been.
That is why it is easy to ignore. A 0.22% charge on £10,000 is about £22 in the first year. The point of this calculator is to show what that small percentage turns into once it is applied every year to a growing pot.
Example: 0.07% vs 0.22% over 25 years
£10,000 to begin, £300 a month, an assumed 6% a year before fees, for 25 years. Only the fund fee changes.
- At 0.07%: the pot ends at £249,552, after £1,765 of fees.
- At 0.22%: the pot ends at £243,271, after £5,453 of fees.
- Difference: £6,281, on £100,000 of identical contributions.
The gap is larger than the difference in fees paid (£3,688), because every pound taken as a fee also stops growing. With no fee at all the same plan would reach £252,548, so the 0.22% fee costs £9,276 in total — £5,453 in fees and the rest in growth those fees would have earned.
Time is what makes a small fee big
Same plan, same two fees, only the horizon changing:
| Years | At 0.07% | At 0.22% | Difference |
|---|---|---|---|
| 5 | £34,335 | £34,155 | £180 |
| 10 | £67,045 | £66,381 | £664 |
| 20 | £170,113 | £166,740 | £3,373 |
| 25 | £249,552 | £243,271 | £6,281 |
| 30 | £356,331 | £345,377 | £10,954 |
| 40 | £692,786 | £663,353 | £29,433 |
Over five years the difference is £180. Over forty it is £29,433. The fee percentage never changed — the pot it applies to did.
Wider gaps work the same way at a larger scale: on the same plan, a 0.5% fee against a 1.5% fee leaves £232,038 against £196,637 after 25 years, a difference of £35,401.
What this calculator does not tell you
- Which fund is better. It assumes both funds earn exactly the same gross return. Real funds hold different things and behave differently, so a cheaper fund is not automatically the right one. This page isolates the cost of the fee and nothing else.
- What returns will be. Returns are not constant and can be negative. The rate is an assumption you choose; run a cautious one as well as an optimistic one.
- Every possible cost. Some funds and platforms have other charges, such as dealing costs or fixed fees. Only percentage fees are modelled here.
- Tax. No tax is modelled. Depending on the account you hold the fund in, and on your circumstances, tax may apply outside the model.
The formula
Each fee is treated as an annual percentage deducted from the return. That gives a net rate for each fund, which is then compounded monthly with your contribution added at the end of each month:
- i — (assumed return − fund fee − platform fee) ÷ 12
- N — years × 12
- P — starting amount; PMT — monthly contribution
- Fees paid — the sum of each month's fee, (fund fee + platform fee) ÷ 12 × the balance that month
This is a simplification. In practice fund charges are taken from the fund's assets on the provider's own schedule, and platform fees may be charged differently; the effect over long periods is close to a straight reduction in the yearly return, which is what is modelled here.
See the formula with your own numbers
These update live from the calculator inputs above.
Frequently asked questions
What is an OCF?
The ongoing charges figure is the yearly cost of running a fund, shown as a percentage of what you hold in it. It is not billed to you; it comes out of the fund, so you see it only as a slightly lower return.
Is a 0.15% difference really worth worrying about?
Over one year it is small. In the default example — £10,000 plus £300 a month for 25 years at an assumed 6% — 0.07% instead of 0.22% leaves £6,281 more, and the gap keeps widening the longer the money stays invested. Whether that matters to you is your call; the calculator just puts a pound figure on it.
Why is the difference bigger than the fees paid?
Money taken as a fee is no longer invested, so it also loses the growth it would have earned. In the default example a 0.22% fee takes £5,453 in fees, but leaves the pot £9,276 below a no-fee pot.
Should I include the platform fee?
If you pay one, yes, to see the total cost. A percentage platform fee applies to both funds in this calculator, so it lowers both pots; the comparison between the two funds is driven by the fund fees.
Is a cheaper fund always better?
Not necessarily. Funds differ in what they hold and how they behave, and this calculator assumes both earn the same gross return. It isolates the cost of the fee only. It is an illustration, not a recommendation.
Method & sources
- Calculation: Monthly compounding at (assumed return − fund fee − platform fee) ÷ 12, contributions at the end of each month. Fees are modelled as an annual percentage deducted from the return — a simplification, stated above. Constant return; no tax, dealing costs or fixed charges.
- Verification: The engine is checked against the closed-form future-value formula in an automated test (
test/fund-fee.test.js). - Reviewed: .
Educational illustration only, not personal financial advice. Capital at risk: investments can fall as well as rise and you may get back less than you put in. Tax rules can change and depend on your circumstances.
Run your own numbers
Enter the two fees you are comparing, your contributions and your time horizon, and see the gap in pounds.
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