How these guides are researched

Every figure and every rule on this site comes from a named, dated source: the legislation itself where legislation exists, and otherwise the government agency that administers it. Each source is listed at the foot of the guide and linked, so any sentence here can be checked against the thing it came from. Where no official figure has been published, the guide says so rather than estimating one.

Where the figures come from

Four kinds of source are used, and they are ranked. A guide reaches for the highest rung that actually answers the question in front of it.

1LegislationThe Act or regulation itself. Social Security Act 2018, KiwiSaver Act 2006, the Agreement with Australia, the Internal Revenue Code.

2The administering agencyWork and Income, Inland Revenue, Services Australia, the Australian Taxation Office, the Social Security Administration, the IRS.

3A regulatorUsed where the question is how a scheme must behave rather than what the law says.

4Official statisticsStats NZ, the Australian Bureau of Statistics, the US Bureau of Labor Statistics. Facts about a population, never about a rule.

Not citedNews, commentary, forums, anything published by a bank, fund, adviser or scheme, and research centres and industry bodies. If a figure can only be traced to one of these, it is treated as unpublished.

A guide reaches for the highest rung that answers the question. Nothing below the line is cited, however well written it is, because it is a step removed from the rule and can go out of date without saying so.

Every source in every guide carries four things: its name, its publisher, the date the source itself carries, and a link. Those four live in one place inside the guide's own file, and that one place is what the page's source list, the structured data search engines read, and the sitemap are all built from. That is deliberate. It means what a person reads and what a machine is told about the same page cannot drift apart.

What is not used as a source

News articles. Commentary. Blogs and forums. Anything published by a bank, a fund, an adviser or a scheme provider. Research centres and industry bodies, including good ones.

Not because all of it is wrong, but because it sits a step away from the rule. A summary can go out of date without saying so, can be right about one country and wrong about the other, and cannot be relied on without going to the source anyway. If a claim can only be traced to one of those places, this site treats it as unpublished.

No commercial provider, fund or product is named anywhere in these guides. Which KiwiSaver scheme or which super fund someone is in makes no difference to any of the rules explained here, so naming one would add nothing except the appearance of a preference.

When there is no published figure

The phrase that turns up occasionally is “no published figure found”, and it is meant literally.

Plenty of cross-border questions have no published answer. A rule can exist without anyone having published how it applies to a particular pair of countries. A tax authority can simply never have ruled on a foreign scheme. In those places a plausible number could be reasoned toward, and it would be worse than saying nothing, because on the page it would look exactly like the sourced figures sitting next to it.

So nothing here is estimated, interpolated or inferred from a rule that looks similar. A gap is shown as a gap.

What the dates mean

Two kinds of date appear on a guide, and they are not the same thing.

Each source carries the date the source declares about itself: a page's “last reviewed”, a rate table's “as at”, the version date of an Act. Not the date it happened to be read. That way you can judge for yourself whether a source was current when it was used, which matters most on the questions where the law changed recently.

The guide itself carries an Updated date, which is when it was last checked against its own sources. That one is enforced rather than trusted: a test fails once any guide's date is more than twelve months old, so a page cannot sit here quietly ageing while its rule moves on without it.

What the tool itself does

The calculator is a year-by-year simulation. It walks forward one year at a time from now to the end of the plan, and within each year it adds contributions, applies the growth rate chosen for each account, takes tax, pays any government pension the person has reached the age for, and takes out what the plan is spending. Nothing is averaged across the whole period, because the order things happen in is most of the answer.

Amounts are entered and shown in today's money and grown by the inflation rate chosen for the plan, so a figure forty years out can be compared with what the same money buys now.

Inflation. Three settings per country, each built from that country's central bank target band and its official consumer price index release, and each carrying the date of the release it came from. Or your own number instead.

Currencies. Exchange rates are fetched when the page loads and re-checked while it is open. A dated snapshot in the code is used only if that fetch fails.

Tax and pensions. Each person's income is taxed on their own country's brackets. New Zealand Superannuation is applied at the after-tax rate Work and Income publishes. Australia's Age Pension is worked out on the assets test, including its taper.

Every one of those figures is a number written into the code beside a note saying where it came from and when it was last checked. They move on four dates a year, so they are reviewed quarterly against their sources, a test fails once a review is more than four months old, and a checklist is raised automatically each quarter.

One place the bar is lower, and it is worth naming rather than burying. The starting figures offered for what a year of retirement costs come from published benchmarks, and the New Zealand and Australian ones are published by a university research centre and an industry body rather than a government. They are offered as a number to start from and change, each is labelled with where it came from, and they are the one part of the site held to a looser standard than the guides.

What is not modelled

This list is more useful than a longer one of features, because it is where an output can be trusted further than it deserves.

The finer parts of Australia's Age Pension. Both means tests are applied, deeming and the Work Bonus included, but not Rent Assistance, the Work Bonus balance that builds up in the years you are not working, or the older transitional rate.
One country's pension taken off another's. The guides explain both directions at length: an overseas pension deducted from New Zealand Superannuation, and New Zealand Superannuation deducted from the Age Pension. The model applies neither, so a household with pensions from two countries may be shown both in full.
United States state income tax. Federal brackets only, and the single filer's set of them.
The tax treatment of moving money between countries: the four-year window, the schedule and formula methods, and anything else that turns on when you became tax resident somewhere.
Market ups and downs. One growth rate per account, optionally easing down as the access age approaches. No random returns, and so no sense of what a bad first few years would do.
Health and aged care costs, and any means-tested subsidy towards them.
Trusts, businesses, and property other than as a balance you enter yourself.

When a rule is unclear

Several of these rules are unclear in their published form, and the cross-border ones especially. Two countries wrote them separately, decades apart, without much thought for the person standing in both.

Where that happens the guide says what the source says, quotes the words that carry the weight, and stops. Where two agencies describe the same rule differently, both are named and the difference is pointed out rather than quietly resolved in favour of the tidier one. Where a rule turns on a fact that only an agency can determine, the guide says which agency decides it and what they are deciding.

What these pages are not

They are descriptions of published rules, written for the person the rules land on. They are general, they take no account of anyone's circumstances, and none of them tells a reader what to do with their money. Nothing here replaces a determination by the agency that administers the rule in question.

If you find something on this site that its source does not support, that is a defect and worth reporting as one.