Comparison
Flat Fee vs Percentage Fee: Where the Cheaper Structure Changes
At what portfolio value does a flat annual fee cost less than a percentage-based annual fee, and how does the ordering change on either side of that value?
The short answer
A US$500.00 flat annual fee and a 1.00% annual percentage fee cost exactly the same at a portfolio of US$50,000.00. Below that value the percentage fee charges less; above it the flat fee does.
At US$25,000.00 the percentage fee is US$250.00 against the flat US$500.00. At US$250,000.00 it is US$2,500.00 against the same US$500.00. The flat charge did not move; the portfolio did.
- Who it applies to
- Two annual prices of different shapes — one flat charge and one percentage rate — compared at a portfolio value. It compares price structures, not named products or providers.
- What this does not tell you
- It establishes which structure charges less in annual money at a portfolio size, and nothing else. It does not establish that the cheaper structure is the better arrangement, and it prices nothing either fee pays for.
An exact identity rather than a projection: two quoted annual prices are compared directly, so no calculation-model version, horizon or return assumption enters the answer.
What is being compared
Two prices for one year, held against each other at a series of portfolio values. Nothing varies between rows except the size of the portfolio, and the two prices themselves never change.
| Flat annual fee | US$500.00 a year, whatever the portfolio is worth |
|---|---|
| Annual percentage fee | 1.00% a year of the portfolio value |
| Portfolio values compared | US$10,000.00 · US$25,000.00 · US$50,000.00 · US$100,000.00 · US$250,000.00 · US$500,000.00 |
| Quantity compared | The annual charge each structure states, for one year |
| Horizon | None. Nothing is projected forward and no year is compounded |
| Assumed return | None. The comparison does not depend on one |
| Contributions, tax and inflation | Not modelled anywhere on this page |
Both prices are illustrative: figures chosen so the boundary can be located and read, not a survey of what any platform, adviser or product charges. No provider is named, and nothing here reports a market rate.
Where the boundary comes from
A percentage fee is an annual charge of portfolio value × fee rate. A flat fee is an annual charge of the same amount at every portfolio value. The two are equal at exactly one portfolio value, and setting them equal gives it directly:
break-even portfolio value = flat annual fee ÷ percentage fee rate
With the prices above that is US$500.00 ÷ 1.00%, or US$50,000.00. There is one division in it and no horizon, which is why the answer is exact and why it does not move when an assumed return does.
The rate is used as a decimal throughout — 1.00% is 0.01 — which is the same convention the calculator applies internally, converted once at the point a percentage is read.
What each structure charges, either side of the boundary
The flat charge is the same in every row. The percentage charge rises with the portfolio, in a straight line, and crosses the flat charge once.
| Portfolio value | Flat fee | 1.00% fee | Flat fee as a share | Cheaper |
|---|---|---|---|---|
| US$10,000.00 | US$500.00 | US$100.00 | 5.00% | The percentage fee |
| US$25,000.00 | US$500.00 | US$250.00 | 2.00% | The percentage fee |
| US$50,000.00 | US$500.00 | US$500.00 | 1.00% | Neither — they are equal |
| US$100,000.00 | US$500.00 | US$1,000.00 | 0.50% | The flat fee |
| US$250,000.00 | US$500.00 | US$2,500.00 | 0.20% | The flat fee |
| US$500,000.00 | US$500.00 | US$5,000.00 | 0.10% | The flat fee |
The fourth column is the same fact read backwards, and it is the quickest way to apply the boundary to prices this page does not list. A flat fee is a percentage fee, at a rate that falls as the portfolio grows: US$500.00 is 5.00% of US$10,000.00 and 0.20% of US$250,000.00. Where that falling rate meets the quoted 1.00% is the break-even, which is why the two structures are equal at US$50,000.00 and nowhere else.
How to read the boundary
- Below US$50,000.00
- The percentage fee charges less in annual money, because a rate applied to a smaller portfolio is a smaller amount while the flat charge stays where it is. At US$25,000.00 the difference is US$250.00 a year.
- At US$50,000.00
- The two annual charges are equal, at US$500.00 each. This is the only portfolio value at which they are, and it is a statement about price alone.
- Above US$50,000.00
- The ordering reverses and the flat fee charges less, by a margin that keeps widening: US$2,000.00 a year at US$250,000.00, and US$4,500.00 at US$500,000.00.
The widening is the percentage fee's own arithmetic and nothing more: it is a fixed share of a growing number, so it grows with it, while a flat charge by definition does not.
The same boundary at other prices
One pair locates one boundary. A small deliberate set shows how it moves, and makes the rule usable on a pair this page does not list.
| Flat annual fee | against 0.20% a year | against 0.50% a year | against 1.00% a year |
|---|---|---|---|
| US$120.00 | US$60,000.00 | US$24,000.00 | US$12,000.00 |
| US$250.00 | US$125,000.00 | US$50,000.00 | US$25,000.00 |
| US$500.00 | US$250,000.00 | US$100,000.00 | US$50,000.00 |
Read a row to see the boundary fall as the quoted rate rises, and a column to see it rise in proportion to the flat charge. Only the ratio of the two prices decides it, which is why US$500.00 against 1.00% and US$250.00 against 0.50% both break even at exactly US$50,000.00.
The set stops at nine on purpose. Every additional row would restate one division a reader can already do, and a page per combination would be a numeric-permutation family rather than an answer.
Costing less is not the same as being better
Everything above prices one variable, and the boundary it finds is a boundary in price alone. Two arrangements that charge differently can also differ in:
- what is included, and what is charged for separately
- advice, and who is accountable for it
- custody and platform functionality
- minimum balances and eligibility
- transaction and dealing costs
- other charges the headline price does not contain
- tax treatment, where it differs
- service, and what happens when something goes wrong
- what it costs in time and risk to move
Equal annual fees do not make two arrangements equivalent, and a lower annual fee does not establish that one is the better choice. The crossover says which price is smaller at a portfolio size. Whether the difference is worth what it buys is a judgement about two specific arrangements, for a specific person, and arithmetic cannot reach it.
Neither structure is presented as the sensible default. A flat charge is proportionally heavier on a small portfolio and a percentage charge grows without limit on a large one, and which of those matters depends entirely on a portfolio this page does not know.
This page belongs to a wider subject. Explore the Investment fees topic to see which UBWHY asset answers which question.
What this comparison does not determine
The figures on this page are exact arithmetic on two illustrative prices. They are not market rates, quoted charges, historical costs or a forecast of anything. The comparison cannot determine:
- whether either structure is a better product, service or arrangement
- what either provider does for the fee, which is not a quantity arithmetic can see
- transaction, dealing, foreign-exchange, entry or exit charges, none of which is modelled here
- minimum balances, tiered rates, capped percentage fees or discounts at scale
- what a fee does to an outcome over a horizon, which is the calculator’s question
- tax of any kind, and no wrapper, allowance, jurisdiction or rate is modelled
- inflation, so every figure here is nominal
- what any real platform, adviser or product actually charges
- whether switching is worthwhile, or what switching would cost
It also assumes each price is the whole price. A headline fee that sits above dealing charges, a foreign-exchange spread or an exit fee is not the annual cost, and no boundary computed from the headline alone is either.
None of this is financial, legal or tax advice, and no product, provider or platform is recommended, ranked or named anywhere on this page.
Where these figures come from
Every number above is produced at build time from break-even portfolio value = flat annual fee ÷ percentage fee rate, applied to the two prices in the comparison set. Nothing on this page is typed by hand.
There is no calculation-model version behind them, and that absence is the point. The crossover is a single division on two stated prices rather than a projection, so it inherits no horizon, no assumed return and no contribution schedule. Its regression suite holds every published figure against a second, independently written implementation of the same identity — two implementations that agree are evidence, one checked against itself is not.
What a fee does after this boundary is decided is a different calculation, and Investment Fee Drag Calculator is the authority for it. That model — Investment Fee Drag v1.0 — compounds a fee month by month over a horizon you supply, and nothing on this page substitutes for it.