FX Fee Tier Break-Even Calculator
Several New Zealand investing platforms now price foreign exchange in tiers: pay nothing and accept a high conversion rate, or pay a fixed annual membership and get a lower one. It is a genuinely useful structure and it produces a decision most investors get wrong in one of two directions, either staying on a free tier while paying hundreds a year in avoidable conversion costs, or upgrading to the most expensive tier on the assumption that more is better. Neither is obvious without doing the arithmetic, because the answer depends entirely on how much you convert. This page fixes that. Every tier fee and every rate is an input, so it works for any platform with this structure rather than being tied to one, and it reports two things: the total annual cost under each tier at your volume, and the break-even volume between every pair of tiers. The second output is the more useful one, because it does not go out of date when your circumstances change. Knowing that a tier starts paying for itself at $5,555.56 of annual conversions tells you what to do now and also tells you when to revisit the decision, which a single answer at today's volume cannot.
Break-even volume between two tiers = (fee of the dearer tier − fee of the cheaper tier) / (rate of the cheaper-membership tier − rate of the dearer-membership tier), with the rates expressed as decimals. Where the rate difference is zero there is no break-even and the lower fee always wins.
Winning bands are derived by evaluating every tier at the break-even points and reporting which is cheapest in each interval.
The membership fee is treated as fully attributable to the FX decision. That is the conservative reading and it is correct where the lower rate is the only reason to upgrade. If the tier delivers other value you would pay for anyway, attribute only part of the fee.
Volume means the amount converted, not the value of the portfolio and not the number of trades. A platform charging FX per conversion at a flat percentage produces the same cost whether that volume arrives in one transaction or fifty.
Monthly billing should be entered as the annual equivalent. A $5 monthly tier is $60 a year, not $5.
Not financial advice. Last verified: August 2026.
Total annual cost at $24,000.00 of conversions
| Tier | Annual fee | FX rate | FX cost | Total | vs cheapest |
|---|---|---|---|---|---|
| Tier 1 | $0.00 | 1.5% | $360.00 | $360.00 | $166.00 |
| Tier 2 | $50.00 | 0.6% | $144.00 | $194.00 | - |
| Tier 3 | $150.00 | 0.4% | $96.00 | $246.00 | $52.00 |
Where each tier starts winning
| Tier 1 against tier 2 | $5,555.56 |
| Tier 2 against tier 3 | $50,000.00 |
| Tier 1 against tier 3 | $13,636.36 |
Each figure is the annual conversion volume at which those two tiers cost exactly the same. Below it the lower membership fee wins; above it the lower FX rate does.
The bands, in plain terms
| If you convert | Cheapest tier |
|---|---|
| Under $5,555.56 a year | Tier 1 |
| $5,555.56 to $50,000.00 a year | Tier 2 |
| Over $50,000.00 a year | Tier 3 |
What the choice is worth over time
| Cost on the cheapest tier, one year | $194.00 |
| Cost on the dearest tier, one year | $360.00 |
| Difference over 5 years | $830.00 |
| Difference over 10 years | $1,660.00 |
Assumes the same annual volume and unchanged tier pricing throughout. It ignores the returns you would have earned on the money not spent, so the true difference is larger.
A Fixed Fee Against A Variable Rate
Tiered FX pricing sets up a straightforward trade: pay a known amount every year to reduce a percentage you pay on every conversion. Whether that trade is good depends on one thing only, which is how much you convert.
It is worth being precise about why people get this wrong. The free tier feels safe because its cost is zero and visible. The conversion cost is neither: it is deducted inside a transaction, denominated in the currency you are buying, and never invoiced. An investor converting $24,000.00 a year on a 1.50% rate pays $360.00 without ever seeing a bill for it.
Worked Example: $24,000 A Year
Three tiers: free at 1.50%, $50.00 a year at 0.60%, and $150.00 a year at 0.40%.
At $24,000.00 of annual conversions the free tier costs $360.00, all of it in FX. The middle tier costs $50.00 plus $144.00, which is $194.00. The top tier costs $150.00 plus $96.00, which is $246.00.
The middle tier wins by $166.00 against the free one and by $52.00 against the top one. Both of the obvious instincts, staying free and buying the best, are wrong at this volume.
The Break-Even Is The Number To Remember
A single answer at today's volume goes out of date the moment your circumstances change. The break-even volumes do not.
Moving from the free tier to the $50.00 tier costs $50.00 more and saves 0.90 percentage points. Fifty divided by 0.009 is $5,555.56. Convert more than that in a year and the paid tier is cheaper.
Moving from the $50.00 tier to the $150.00 one costs $100.00 more and saves only 0.20 percentage points. One hundred divided by 0.002 is $50,000.00, which is a great deal of conversion volume. The top tier is genuinely for high-volume investors and is an expensive mistake for anyone else.
Read The Bands, Not The Answer
The three bands on the worked example are: free below $5,555.56, middle between $5,555.56 and $50,000.00, and top above $50,000.00.
Expressed monthly, the middle tier starts paying for itself at about $463 a month of conversions, which is a modest regular investment. The top tier needs roughly $4,167 a month. Most regular investors sit squarely in the middle band and stay there for years.
If your volume sits close to a break-even, choose the cheaper membership. The cost of being on a low tier during a heavy year is a fraction of a percentage point on the excess; the cost of paying for a tier you did not use is the entire fee.
What This Deliberately Leaves Out
Paid tiers usually do more than lower an FX rate. They may unlock funds with lower management fees, remove other charges, or add automation. Any of those can change the answer, sometimes decisively.
This page isolates the FX comparison on purpose, so that one component is visible rather than buried in a bundle. If a tier also reduces your fund fees, work that saving out separately and add it. Our fixed fee versus percentage fee calculator handles the fund fee version of the same arithmetic, and our membership tier break-even calculator combines both into a single view.
The Same Arithmetic, Elsewhere
Nothing here is specific to foreign exchange. Any fixed fee bought against a variable rate behaves identically: a subscription that reduces brokerage, an annual platform charge that lowers a management fee, a package that cuts a transaction cost. Divide the fee difference by the rate difference and you have the break-even.
It is worth running whenever a provider offers to sell you a discount. The question is never whether the discount is real, it is whether you buy enough of the thing being discounted. Our US share FX cost calculator shows what a single conversion costs at any given rate, which is the input this page annualises.
Related NZ Investing Cost Calculators
- US Share FX Cost Calculator: what one conversion costs at a given rate.
- Membership Tier Break-Even Calculator: tiers compared on fund fees as well as FX.
- Fixed Fee vs Percentage Fee Calculator: the same trade applied to management fees.
- FX Spread vs Fee Calculator: when the cost is hidden in the rate rather than charged as a fee.
- Total Cost of Owning a US ETF: every cost layer together.
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