Fund Fee Calculator UK: What Your OCF Really Costs

Enter two funds' ongoing charges (OCF) and your platform fee to see what each one costs in pounds over your investing horizon, and how much bigger the cheaper pot ends up. The point most people miss: the fee you pay directly is only part of the cost. Every pound taken in charges also stops compounding, so over 20 or 30 years the growth you lose can come close to the fees themselves.

How this calculator works

Each month it adds your contribution, grows the pot by the monthly equivalent of your expected return, then takes one twelfth of the yearly charge, which is roughly how funds and platforms deduct fees in practice. It runs the same sums three times: once with no charges at all, once for Fund A and once for Fund B. The gap between the no-charge pot and each fund's pot is the true cost of that fund's charges, split into two parts:

• Fees paid: the pounds actually deducted over the whole period.
• Growth lost: the returns those pounds would have earned had they stayed invested.

Because the fee is a percentage of a pot that keeps growing, it gets bigger in pounds every year even if the percentage never changes. That is why a gap of half a percent looks small at year one and large at year thirty.

Where to find the real charge

The OCF is on every fund's factsheet and key information document. It covers the fund manager's fee and running costs, but not the trading costs inside the fund, which UK providers publish separately as transaction costs under the MiFID costs and charges disclosure. If you want the fullest comparison, add the two together for each fund. Your platform fee sits on top: enter it as a percentage if your platform charges one, or 0 if it charges a flat monthly fee or nothing. Our platform fee calculator compares those platform charges directly, and our guide to what the OCF includes explains the rest.

What the result does not tell you

A cheaper fund is only better if it gives you the same exposure. Comparing a global tracker against a global tracker, or an S&P 500 fund against another S&P 500 fund, is a fair test. Comparing a tracker with an active fund assumes both earn the same return before charges, which this calculator does by design; the active fund has to beat the market by at least its extra charge every year just to draw level. The return you enter is an assumption, not a forecast, and real returns vary from year to year. Results are in future pounds and ignore inflation, tax and dealing charges, so treat them as a guide to the size of the gap rather than a promise of what you will end up with. This is not financial advice.