Investment Fee Calculator

Why a 1% fee does not cost 1%

The intuition most people carry is that a 1% annual fee removes about 1% a year, so over thirty years it costs roughly a third of the growth. The real figure is far worse, and the reason is the same mechanism that makes investing work in the first place.

A fee taken in year one does not just remove that money. It removes every year of growth that money would have produced for the remaining twenty-nine years. Do that annually, on a balance that is itself compounding, and the shortfall grows geometrically rather than linearly.

Try it above. Set a thirty-year horizon and compare a 0.15% fee against 1.25%. The difference is not the 1.1% gap you paid each year — it is typically a quarter or more of the entire final balance.

What the calculator is doing

Each month it applies one twelfth of the net annual return, then adds your contribution. Net return is simply your gross return minus the fee, which is how a percentage-based annual charge actually behaves: it is deducted from the value of your holdings, so it reduces the rate at which they grow.

Both lines on the chart receive identical contributions and identical gross returns. The only difference between them is the fee. Everything you see in the gap comes from that one number.

Two deliberate simplifications:

• The return is smooth. Real markets deliver sequences, not averages. This is fine for comparing two fee levels, because the sequence affects both identically, but it is not a forecast of what you will have.
• Fees are charged as a percentage of the balance. Flat annual account fees and per-trade costs behave differently and are not modelled here, though you can approximate them by expressing them as a percentage of your expected average balance.

Finding your actual number

This is the part that takes effort, because the figure you need is rarely presented anywhere as a single number. Costs stack, and each layer is disclosed in a different document.

Add them together. A 1% adviser fee sitting on top of funds charging 0.75% is a 1.75% all-in cost, not 1%. That layering is the single most common reason people underestimate what they pay, and it is why the calculator asks for your all-in figure rather than just the fund charge.

If you hold several funds, weight the charges by how much is in each rather than averaging them flat.

What counts as high, and what counts as low

There is no universal threshold, but there are recognisable bands. As orientation rather than a rule:

• Under 0.25% all-in is achievable with broad index funds held directly on a low-cost platform
• 0.25% to 0.75% is typical for a straightforward portfolio on a mainstream platform
• 0.75% to 1.5% usually indicates either active management or an advice relationship
• Above 1.5% should be producing something specific and identifiable in return

That last point is the useful test. A fee is not automatically wrong; it is wrong when you cannot say what it buys. Run your own figure through the calculator, look at the number, and ask whether you are receiving something worth that.

What is genuinely worth paying for

Being even-handed about this matters, because the low-cost argument is often pushed further than the evidence supports.

• Behavioural coaching. An adviser who stops you selling everything during a downturn can preserve more than they cost over a lifetime. The cost of a badly timed exit dwarfs the cost of advice.
• Genuine complexity. Estate planning, business ownership, concentrated holdings, cross-border tax positions, or divorce settlements are all situations where competent advice earns its fee comfortably.
• Actually starting. A 1% fee on an account that exists beats 0.1% on an account you never opened. If paying someone is what gets you invested, that is a real service.

What is not worth paying for is a fee attached to nothing in particular: an expensive fund tracking the same index as a cheap one, a platform charging more for the same holdings, or an ongoing advice charge for a relationship that produces one review a year.

The questions to ask

If you take one action after using this tool, make it these five questions to your provider or adviser, in writing:

1. What is my all-in annual cost, as a single percentage, including fund charges, platform fees and advice?
2. What did I pay in cash terms last year?
3. Are you a fiduciary, or otherwise obliged to act in my interest?
4. Do you receive any payment from the products you recommend, including commission or revenue sharing?
5. What am I receiving for this fee that I could not obtain for less?

Vagueness in response to question one is itself an answer. The figure exists and is knowable; a provider unwilling to state it plainly is telling you something.

A note on tax wrappers

The calculator models cost, not tax. In practice the two interact, and the interaction usually favours dealing with tax first.

In the US, contributing to a 401(k) or IRA changes the tax treatment of the money before any fee applies. In the UK, an ISA or pension does the equivalent. A high-fee account inside a tax wrapper can easily beat a low-fee account outside one, because the tax saved often exceeds the fee paid.

So the sensible order is: use the available tax-advantaged space first, then minimise costs within it. Reversing that order optimises the smaller number.

Reading the chart

The two lines start together and separate slowly. For the first several years the gap looks trivial, which is exactly why fees are easy to ignore when you are choosing a provider — the cost of the decision is invisible at the point you make it.

Watch the last third of the chart. That is where the compounding of the fee shows up, and it is money removed from the years in which your balance is largest. The decision was made decades earlier.

This is the same mechanism described in how investment fees compound, and the mirror image of the growth shown in compound interest explained. If you want to see what the underlying growth looks like without the fee comparison, our investment calculator projects a single scenario.

Sharing your figures

The Copy link button encodes your inputs into the page address, so you can send the exact comparison to someone else — or to your adviser, which is a reasonable way to open the conversation about question one above.

Your numbers travel in the link and nowhere else. Nothing is transmitted to us and nothing is stored on a server.