Which exchange rate to use for FIF: IRD mid-month, end-of-month and rolling rates

Every FIF figure has to be in New Zealand dollars, and the rate you use can move the answer by hundreds of dollars. Inland Revenue lets you choose one method and apply it consistently to all your holdings: actual rates on each day (for which it accepts its published mid-month rate), or a rolling 12-month average (IR461 p13). Inland Revenue publishes end-of-month, mid-month and rolling average rates on its overseas currency page. This guide explains each method, the consistency rule, and how to read the tables.

The three methods

For every FIF method except attributable FIF income, you choose one of these and apply it to all your attributing interests (IR461 p13; TIB Vol 31 No 11 p2; ITA s EX 57):

1. Actual rate on the day of each amount or valuation. “For the actual rate, we accept the mid-month rate as equivalent to an actual rate for transactions occurring in that month” (IR461 p13 note).
2. Rolling 12-month average rate, for a 12-month income year.
3. Rolling average built from mid-month rates, for a period longer or shorter than 12 months (for example the year you arrive or leave).

The rolling average cannot be used for attributable FIF income (IR461 p13), which is rarely relevant to individual investors.

The consistency rule

Two layers of consistency apply:

• Across holdings. The same method for all your attributing interests in the year (IR461 p13). You cannot use the rolling rate for your US shares and actual rates for your UK shares.
• Across years for the rolling average. Inland Revenue’s currency page says: “If you start using this method [rolling average] to calculate FIF income, you must keep using it every year” (IRD overseas currency page, 4 November 2026).

So think before you move to the rolling average: it is a one-way door. Our calculators ask which method you used last year and warn you if a change looks like it breaks the rule. Moving between actual-rate approaches (IRD’s published mid-month and end-of-month figures, or your own daily rates) is not flagged by our engine, but keep your method steady and documented either way.

What Inland Revenue publishes

Inland Revenue’s overseas currency page (last updated 4 November 2026) has PDF tables for the 2021 to 2027 years:

• End-of-month rates, one per month;
• Mid-month rates, dated the 15th;
• Rolling 12-month average rates, also dated the 15th.

The 2026 files cover 17 currencies: AUD, CAD, CNY, EUR, HKD, INR, IDR, JPY, KRW, MYR, TWD, PHP, SGD, THB, GBP, USD and VND. Rates are quoted as foreign currency per NZ$1, so you divide the foreign amount by the rate to get NZ dollars, and round the rate to 4 decimal places where possible (TIB Vol 31 No 11 p2).

The page names the Reserve Bank of New Zealand as the source. A 2019 Tax Information Bulletin said Bloomberg wholesale rates; we have not found when that changed.

Our exchange rates tool holds every rate from those PDFs and converts any amount, and the same data is published as open data. The latest end-of-month figure we hold is for 31 October 2026.

One amount, four rates

Here is US$10,000 converted at the US dollar rates Inland Revenue published around the end of the 2025/26 year:

The gap between the highest and lowest conversion is more than $470 on US$10,000. On a large CV calculation, where the opening and closing values are both converted, that can decide whether CV or FDR is lower.

Which rate goes where

Inland Revenue says which methods are allowed, but not which published table to use for each amount. Our default, using IRD rates as actual rates, is:

Using the previous year’s rate for the opening value under the rolling method comes from s EX 51(5) for CV; applying it to FDR as well is our reading. Using 15 March as the rolling figure for a year ending 31 March is also our reading. Both are listed on our methodology page.

Worked example. Your US holdings were worth US$30,000 on 1 April 2025.

The rolling method gives about $97 less FIF income here, but in another year it could give more. Because you are locked in once you start, pick on principle (simplicity, matching your records), not on one year’s result.

Years that are not 12 months

If your FIF period is shorter or longer than 12 months, for example the year you arrive in New Zealand, the rolling method uses the average of the mid-month rates for the months in the period. TIB Vol 31 No 11 (pp3 to 4) gives an example: five Singapore dollar mid-month rates of 0.8982, 0.8903, 0.9112, 0.8956 and 0.8759 average 0.89424, rounded to 0.8942, so SGD 500,000 converts to NZ$559,159.02. Our engine reproduces that figure.

One small note for accuracy: TIB Vol 31 No 11 Example 1 prints $10,766.58 for PHP 350,000 ÷ 32.4776, but the division gives $10,776.66. We test against the correct arithmetic and say so on our methodology page.

Why your broker’s NZ$ figures differ

Platforms often show NZ$ values using their own exchange rates, or the rate on the day you looked. Those figures will rarely match IRD’s tables. Inland Revenue’s rule is about method and consistency, so a platform’s report can be a fine starting point, but check which rate it used and make sure every holding, across every platform, is converted the same way. If you hold US shares on one platform and UK shares on another, converting one set at the platform’s rates and the other at IRD rates would break the same-method rule.

Holdings in currencies IRD does not publish need another source of actual rates; our tool lets you enter your own. Keep a note of where each rate came from (records guide).

Converting a year, step by step

1. Decide your method for the year, and check what you used last year. If it was the rolling average, you stay on it.
2. List every amount that needs converting: 1 April values, 31 March values (for CV), every purchase and sale, and every dividend with its foreign tax.
3. Look up the rate for each amount in Inland Revenue’s tables, or in our rates tool, which holds the rates from the same PDFs.
4. Divide each foreign amount by the rate, and round the NZ$ result to the cent.
5. Apply the same method to every holding on every platform.
6. Write down the method, the table and the date of each rate, and keep it with your FIF records.

Our FIF calculator does all of this with IRD rates by default, or with your own rates if you prefer.

Currency can create FIF income on its own

Inland Revenue notes that FIF income can arise even if shares perform poorly, because of currency movements (IR461 p22 note 5). Under CV, a falling New Zealand dollar raises the NZ$ value of your closing holdings even if share prices are flat. Under FDR, a weak dollar on 31 March raises next year’s opening value and so next year’s 5%.

Rules checked 12 November 2026. General information, not tax advice; check with your accountant.

Questions

Do I multiply or divide by the IRD rate?

Divide. IRD quotes foreign currency per NZ$1, so NZ$ = foreign amount ÷ rate (TIB Vol 31 No 11 p2).

Can I switch from the rolling average back to actual rates?

Inland Revenue says that if you start using the rolling average for FIF income, you must keep using it every year (IRD overseas currency page).

Can I use the mid-month rate instead of the rate on the day?

Yes. IR461 p13 says IRD accepts the mid-month rate as equivalent to an actual rate for transactions in that month.

Can I use different methods for different holdings?

No. One method applies to all your attributing interests in the year (IR461 p13).