About FinLab

What FinLab is

FinLab is a small, independent set of New Zealand personal-finance calculators: take-home pay (PAYE), KiwiSaver first-home withdrawal, borrowing power and mortgage repayments. Each one turns numbers you enter into a clear estimate, using the rates and rules that actually apply in New Zealand — and every calculation runs in your browser.

Why it exists

Most pay and mortgage tools online are attached to a bank, a broker or a lead-generation business, and they are built to move you toward a product. FinLab was created to do the opposite: give a straight answer from the published rules, with the sources shown, and nothing to sell. The aim is that you can check a figure, understand where it comes from, and trust it enough to plan around.

How the calculators are maintained

Every rate, threshold and rule lives in a versioned data file with an effective date, an official source link, and the date it was last checked. The calculators read from those files — no figure is typed inline in the page — so a single update flows through every tool and guide at once. Rules are reviewed when an official source announces a change, and again around 1 April each year when tax-year settings usually move. Where a figure has not been confirmed, it is marked rather than guessed.

Where the data comes from

FinLab does not invent rates. Income tax, ACC, KiwiSaver, student loan, DTI, LVR and first-home figures are taken from official publications:

• Inland Revenue (IRD)
• Reserve Bank of New Zealand (RBNZ)
• Kāinga Ora
• New Zealand legislation, Budget documents and Sorted.org.nz

If a FinLab figure and an official source ever disagree, the official source prevails. The full method and the source behind each number are on the methodology page.

Who publishes FinLab

FinLab is an independently operated New Zealand website. It is not a bank, lender, KiwiSaver provider, broker or government agency, and it is not affiliated with any of them. There is no product to sell and no lead form behind the calculators. The publisher is based in New Zealand and can be reached at support@finlab.co.nz. Corrections, source questions and editorial complaints go to that address; confirmed errors are fixed in the rules files and deployed, as described on the methodology page.

Independence

FinLab does not sell leads, take referral fees, or tailor results to a product. It provides general estimates for educational purposes only — not financial advice. For advice specific to your situation, speak with a licensed financial adviser; see the full disclaimer.

Guides and explainers

Alongside the calculators, FinLab publishes original guides that explain the rules behind each number — tax codes, KiwiSaver withdrawals, deposits, DTI and LVR, serviceability, and mortgage structure. They are written to be read on their own, without a finance background, and they quote the same published rates the tools use. The full set lives on the guides page.

How the site stays free

FinLab is free to use. It shows advertising through Google AdSense so the calculators and guides can stay available without accounts or paywalls. Ads are disclosed on the privacy page. Calculator inputs are still not sent to FinLab or used to target you.

Get in touch

Spotted a figure that looks wrong, or have a question about how a calculator works? The contact page explains how to reach us and what to include so it can be checked quickly.