NZ GST calculator

General information only — not tax advice. These calculators perform standard GST arithmetic (15% rate; extract via ×3÷23) and compare a figure you enter to a published threshold. They do not assess your tax position or tell you what you can claim or must do. Confirm anything that affects your tax with a chartered accountant or at ird.govt.nz. Rate and threshold verified May 2026.

Adding vs. extracting GST

NZ GST is 15%. If you have a GST-exclusive amount (before tax), multiply by 1.15 to get the GST-inclusive price. If you have a GST-inclusive amount and need to separate out the GST component, the formula is price × 3 ÷ 23 (not ÷ 1.15, which gives you the wrong number).

Most NZ contractors quote exclusive of GST and add it on top for GST-registered clients. If you sell to consumers you may quote inclusive. Either's fine. Just be consistent on your invoices. See IRD: How taxable supply information works.

Second-hand goods: the price × 3 ÷ 23 rule

When you buy second-hand goods from a private, unregistered sellerfor business use, there's no GST invoice — but GST is baked into the price the seller originally paid. IRD allows you to claim an input deduction of price × 3 ÷ 23 to recover that embedded GST.

The arithmetic is exact; the eligibility conditions are what vary by situation. You must be GST registered, the purchase must be for taxable business use, and you'll need your own records (listing, receipt, seller details). See the GST guide IR375 for the full rules.

The $60,000 threshold: why it's rolling, not annual

You must register for GST if your turnover exceeds $60,000 in any rolling 12-month period, backward or forward looking. The catch: it's not your tax year. If you had $40k in one financial year and $25k in the first month of the next, you've crossed $60k on the rolling test even though neither year shows $60k.

If you're close, register early — registering late means you may owe GST on past sales you've already invoiced without it. IRD: Registering for GST.