Tools

Reinvestment Charge Against One Dividend

Your platform charges something every time it reinvests a dividend, per holding — a flat amount, or a percentage with a floor and a cap. Below what dividend size is that charge taking more of the payment than you said you would accept, and how many holdings can you afford to run this way?

Every guide on this subject says the same thing and stops: two on a fifty pound dividend is four per cent. Four per cent of what, and at which dividend size does it stop being four per cent? A charge with a floor and a cap is a rate only between them — below the floor it is a fixed amount whose share falls as the payment grows, and above the cap it is a fixed amount again. This page takes your own charge structure and says which of those three you are in, what the payment actually costs you, and how small a dividend can get before the cost passes a line you drew yourself.

What this tool does not decide

Whether reinvesting is worth it. That is an expected return over some horizon, no authority publishes one, and a real charge multiplied by an invented benefit would look like an answer while being an assumption. There is no field here for a return and nowhere to put one.
What your platform charges. This tool publishes no tariff, names no platform, broker or scheme, fetches nothing and has no field to name one with. The figures are yours to enter, and that is why nothing on this page can go out of date.
Which platform is cheaper. A platform differs in far more than one charge, and a page that priced this one and implied a ranking would be reasoning from the only number it happens to hold.
What the shares are worth afterwards. Everything here is a cost, taken at the moment of the purchase. No price movement, no yield and no total return appears in this arithmetic anywhere.
Anything about tax on the dividend itself, in any jurisdiction.

Your figures

The interactive calculation runs in your browser and needs local JavaScript, which is currently switched off. Activating the Calculate button does nothing at all: no request is sent and nothing is submitted.

Everything else on this page works without it. The model, the formulas, the timing convention, the worked example, the assumptions and the limitations are all in the methodology below, and the companion explainer covers the mechanism in full.

Your arrangement, in ten numbers

Every charge on this page is yours to enter and this page publishes none. Platforms differ on all of it — some charge a flat amount per holding per payment, some a percentage with a floor and a cap, some nothing at all — and the maintained comparison tables do not carry the column, which is why you are here. Take the figures from your own platform’s charges page. Because nothing is published here, there is nothing on this page that can go out of date. Nothing you type is sent anywhere.

One payment, and what the platform takes out of it

One dividend payment, on one holding

What one holding pays you once, before any charge. There is no currency here and no field for one: every amount on this page comes back in the unit you enter this in. If your holdings pay very different amounts, run the page for the smallest — that is the one the charge does the most damage to.

The charge, as a percentage of the dividend

Enter 1 for one per cent. Enter 0 if your platform charges a flat amount instead — a flat charge is expressed in the two controls below rather than here, because it is the same structure with the floor and the cap set to the same number.

The least the charge can be

The floor. Enter 0 if there is no minimum. For a flat charge, put the flat amount here and the same amount in the next control — a flat charge is a floor and a cap that meet, and it is the only way to express one on this page.

The most the charge can be

The cap. Enter the same figure as the minimum for a flat charge. If your platform caps nothing, enter a figure larger than any charge it could produce — the arithmetic then never reaches the cap and the page will say so by naming the regime you are in. A cap below the floor is refused, because no single charge can be both.

Transaction tax on what is actually invested

A tax on the purchase rather than on the dividend. Enter 0 if none applies to you. It behaves differently from everything else here: it is proportional and never dilutes, so a big enough dividend can outgrow a flat charge and can never outgrow a tax.

What happens to the money that is left

How often, how many, and the line you draw

Dividend payments a year, on one holding

4 for quarterly, 2 for twice a year, 12 for monthly. The charge falls on every one of them, which is what turns a small amount into an annual figure.

How many holdings you reinvest this way

The charge is per holding per payment, so this count multiplies everything below it. Enter 1 if you are asking about one holding; the second half of the question this page answers is how many of them a budget will run.

What you will spend on these charges in a year

Across all your holdings, for the year. Enter 0 if the answer is nothing — the page will then report that the budget runs no holdings, which is a true answer rather than an error.

Result

A reinvestment charge is almost never the rate your platform quotes. A flat amount is a rate that falls as the dividend grows; a percentage with a floor and a cap is a rate only between them, and a hyperbola on either side. So the effective cost of reinvesting moves through three regimes as the dividend gets larger — the floor binding, the rate applying, the cap binding — and two platforms a reader is told cannot be compared are usually the same structure at different parameters, met in different regimes. This page publishes which regime your own dividend falls in beside the cost share it produced, because the share on its own does not say which one you are in, and the answer changes with the size of the dividend rather than with the platform.

Enter your ten figures above and select Calculate. Nothing is sent anywhere: the calculation runs in this browser, and no value is stored, shared or placed in the address bar.

The charge on one reinvestment: Not yet calculated
Transaction tax on what is left to invest: Not yet calculated
What one reinvestment costs in total: Not yet calculated
That cost as a share of the dividend: Not yet calculated
Which part of the charge structure you are in: Not yet calculated
The smallest dividend whose cost stays inside your share: Not yet calculated
How much larger your dividend would have to be: Not yet calculated
What is left to invest: Not yet calculated
Whole shares that buys: Not yet calculated
What stays as cash because a whole share did not divide it: Not yet calculated
The share of the dividend that reaches the market: Not yet calculated
A year of this, on one holding: Not yet calculated
A year of this, across your holdings: Not yet calculated
How many holdings your budget runs: Not yet calculated

Every figure here is a cost. Nothing on this page prices what reinvesting is worth, because that is an expected return, no authority publishes one, and a charge multiplied by an invented benefit would look like an answer while being an assumption. The share of a dividend you said you would accept losing is the only place your own view of that benefit enters, and it enters as a line you drew rather than as a return anybody forecast. So the break-even here is a break-even against your own tolerance, and it is not a statement that reinvesting above it pays.

This is arithmetic on ten numbers you supplied. It assumes one charge structure — a rate with a floor and a cap, where a flat charge is the floor and the cap set equal — and a platform that buys whole shares only, so what a whole share does not divide stays as cash. A platform that buys fractional shares is a different arrangement and this is not it with a smaller remainder. It assumes every one of your holdings charges the same, which is unlikely across a portfolio, and it holds the dividend constant across a year rather than following a real payment schedule.

A cost share is not advice to turn reinvestment off, and a break-even is not advice to turn it on. What reinvesting is worth to you depends on what the money would otherwise do, on how long it would sit as cash, on whether you would remember to invest it by hand and on what that would cost instead — none of which is in this arithmetic and none of which this page has a field for. What is published here is what the arrangement costs. What it is worth is not a question ten numbers can answer.

How this is worked out

Why the rate your platform quotes is usually not what you pay

A reinvestment charge is nearly always quoted as one figure — a flat amount per holding per payment, or a percentage with a minimum and a maximum. Neither is a rate on your dividend.A flat amount is a share that falls as the dividend grows, and a percentage with a floor and a cap is a rate only between them. So the effective cost of reinvesting moves through three regimes as the payment gets larger, and which one you are in depends on the size of your dividend rather than on the platform.

Three regimes, and one difference between them that everything else follows from: what is actually charged.
Regime	When you are in it	What is charged	What the share does	The quoted rate
The floor is binding	The rate on your dividend comes to less than the minimum	The minimum, whatever the rate says	Falls as the dividend grows — a fixed amount over a rising number	The quoted rate is not what you pay
The rate applies	The rate on your dividend lands between the minimum and the maximum	The rate, exactly as quoted	Flat — the same share at every dividend in this range	The quoted rate is what you pay
The cap is binding	The rate on your dividend comes to more than the maximum	The maximum, whatever the rate says	Falls again as the dividend grows — a fixed amount over a rising number	The quoted rate is not what you pay

That is why two platforms are so often reported as impossible to compare. They are usually the same structure at different parameters, and a reader meets one of them in the floor regime and the other on its plateau — a fixed amount against a rate, which look like different kinds of thing and are not.

The quantities that follow

The cost share: The charge, plus any transaction tax on what is left to invest, over the dividend. It is the figure the guides state anecdotally and stop at
The regime: Which of the three above produced that share. Two platforms are comparable exactly once this is beside the number, and a reader is usually in a different regime on each of them
The break-even: The smallest dividend whose cost share stays inside the share you said you would accept. It is a threshold against your own line and not against any return
What reaches the market: What is left after the charge, less whatever a whole share does not divide. It is below one less the cost share wherever the remainder is not zero
The holdings a budget runs: A year of this on one holding, divided into what you said you would spend. It is the second half of the question and the half a per-payment figure cannot answer

The arithmetic

Write D for one dividend payment, r for the charge rate,f and c for the floor and the cap, τ for the transaction tax,a for the share you will accept losing, k for payments a year,n for holdings and B for the annual budget:

charge(D) = max(f, min(c, r × D))
cost(D)   = charge(D) + τ × (D − charge(D))
share(D)  = cost(D) ÷ D = charge(D) × (1 − τ) ÷ D + τ

with m = a − τ and ρ = r × (1 − τ):

m ≤ 0    no dividend qualifies — the tax alone is above the line
ρ ≤ m    break-even = f × (1 − τ) ÷ m      the floor is what has to dilute
ρ > m    break-even = c × (1 − τ) ÷ m      the plateau is already too dear

holdings a budget runs = ⌊B ÷ (k × cost(D))⌋

Note where τ sits. It is added to the share rather than multiplied into it, and it is bounded by nothing — which is why a big enough dividend can outgrow a flat charge and can never outgrow a tax. The third branch is the interesting one: a platform whose rate is above the line you drew can still qualify, but only once the cap has taken over, and the dividend that takes is usually far larger than any single holding pays.

What this page will not do, and why it could not

It does not price what reinvesting is worth. That is an expected return over some horizon; no authority publishes one; and a real charge multiplied by an invented benefit would look like an answer while being an assumption.There is no field here for a return, an excess over cash or a horizon, and there is nowhere on this page one could be put. Your own view of that value enters once, as the share of a dividend you say you will accept losing — a line you drew rather than a return anybody forecast. Everything published here is a cost, and the break-even is a break-even against that line and against nothing else.

What you enter, and what this page will never enter for you

A dividend, a charge structure, a tax, a share price, a frequency, a count, a budget and a line.This page publishes no charge and names no platform. The maintained comparison tables do not carry the reinvestment-charge column at all, which is the reason this page exists — and a figure published here would be right for one reader and stale for everybody. Because it holds no such fact, there is nothing on this page that can go out of date.

The limits this calculation imposes on itself

A charge exactly on the boundary between two regimes is reported by where the unbounded rate falls, not by which bound the charge happens to equal. At a floor and a cap set to the same amount the charge equals both, and asking which one it equals would answer arbitrarily.
The cost share is compared with your tolerance on exact equality rather than within a tolerance of its own. Reporting a charge as acceptable while it is measurably over the line you drew is the one reading this arithmetic must not produce.
Every payment is assumed to be the size of the one you entered, every holding to charge the same, and the frequency you entered to apply to all of them. A real portfolio is none of those things, and the annual figures are as good as that assumption.
Whole shares only. A platform that reinvests in fractional shares is a different arrangement, not this one with a smaller remainder, and the residual cash row would be zero rather than small.
Nothing here is conditional on any platform, scheme, broker or jurisdiction, and no figure below describes anybody’s actual tariff.

What is not modelled

what being invested is worth against holding the cash — no return, no excess over cash and no horizon appears anywhere here
a platform that reinvests in fractional shares rather than whole ones
a scheme that pools several holdings’ dividends into one purchase, or one charge
a charge that changes with the size of the account rather than with the size of the dividend
the platform’s own annual or custody fee, which is a separate charge on a different base
tax on the dividend itself, withholding at source, or any relief on either
the price the shares are actually bought at, or when in the day the purchase happens
currency conversion, where the dividend and the share are not in the same currency
the identity of any platform, scheme, broker or jurisdiction

The mechanism behind why a small recurring charge is not a small charge — what a deduction that repeats does over a horizon — is taught in the explainer:how investment fees compound.

Go deeper

The nearest published mechanism
How Investment Fees Compound Into Lost Wealth
Why a small annual investment fee can create a much larger long-term difference, why the second component of that difference is signed, and where the arithmetic stops.
The mistake this page corrects is treating one small charge as too small to be worth a calculation. The explainer is about what a deduction does once it repeats, which is what a charge levied on every holding on every payment is.
Read the explainer: How Investment Fees Compound Into Lost Wealth

Calculation model and corrections

Calculation model: Reinvestment Charge Break-even v1.0
Last reviewed: 29 August 2026
The three regimes, and why the quoted rate is usually not what you pay: The charge is max(floor, min(cap, rate × dividend)). Below the point where the rate reaches the floor, you pay the floor, and its share of the dividend falls as the dividend grows. Between the two bounds you pay the rate, and the share is flat. Above the point where the rate reaches the cap, you pay the cap, and the share falls again. Every result on this page names which of the three your own dividend fell in, because the share alone does not say — and two platforms a reader is told cannot be compared are usually this one structure at different parameters, met in different regimes
What is not here, and why it could not be: The value of being invested rather than holding the cash. It is an expected return, no authority publishes one, and a real charge multiplied by an invented benefit looks like an answer while being an assumption. So there is no return field, no excess-over-cash field and no horizon anywhere in this model, and every figure it publishes is a cost. Your own view of that value enters once, as the share of a dividend you say you will accept losing, and it enters as a line you drew
What a break-even is a break-even against: The share you named, and nothing else. It is the smallest dividend at which the total cost — charge plus any transaction tax on what is left — stops exceeding that share. It is not the dividend above which reinvesting pays, and this page has no way to compute that figure and does not offer one
A flat charge is not a separate mode: It is the floor and the cap set to the same amount, at any rate at all. There is no charge-kind selector here, because the two structures a reader is told are incomparable are the same structure at different parameters — and a mode control would put that distinction back on the page
Why a transaction tax behaves differently from a charge: It is proportional and unbounded, so it never dilutes. A floor is a fixed amount and its share of a dividend falls as the dividend grows; a tax at half a per cent is half a per cent of every dividend there is. That is why "no dividend is large enough" is a reachable answer here and is a different answer from "this charge is large"
Whole shares only: What is left after the charge buys whole shares at the price you entered, and whatever a whole share does not divide stays as cash. The share of the dividend that actually reaches the market is therefore below one less the cost share wherever the remainder is not zero, which is the third leak in this arrangement and the one nothing else combines with the other two. A platform that buys fractional shares is a different arrangement and this model is not it with a smaller remainder
What the annual figures assume: That every payment is the size of the one you entered, that every holding charges the same, and that the frequency you entered applies to all of them. None of that is true of a real portfolio. The count is there because the charge is per holding per payment, so it multiplies everything — and the frozen question asks how many holdings this arrangement can be afforded on
Excluded: Every platform, broker, scheme, jurisdiction and published tariff; the platform’s own annual or custody fee; tax on the dividend itself and any relief on it; withholding at source; currency conversion; the price the shares are actually bought at; fractional-share schemes; pooled purchases across holdings; and whether reinvesting is worth doing
Rounding: Display only; intermediate values remain unrounded

Correction history

The qualification corpus classified this candidate as an extension of Registration Threshold Notch v1.0, on the reasoning that a fixed charge with a floor and a cap against a variable amount is that model’s shape with two boundaries. MODEL-BATCH-06 tested the claim against the model it named and found it false. The notch model exists because a discontinuity in the level creates a range over which earning more leaves the reader worse off; the charge expression here is continuous everywhere, and all three of the notch model’s published quantities — the notch, the break-even and the dead zone — are undefined for it. Built as an extension it would have published a notch of zero and a dead zone of zero on every input, and no check would have failed. It was built as its own model instead, and that is why this page draws no step: there is no jump in it, only a cost share that falls, flattens and falls again.
The break-even is solved in closed form in three branches, and the verifier deliberately does not check the closed form against itself. It recovers the break-even by sweeping the surface the model published and compares the two, so the branch taken and the curve drawn have to agree. That check is what would catch the most likely future defect in this model, which is not an arithmetic slip but a branch condition that is subtly wrong at the boundary between the floor regime and the plateau — the one place where a reader comparing two platforms is most likely to be standing.