How much GST do I add in New Zealand?

GST in New Zealand is 15%. To add GST to a price, multiply by 1.15: a $100 item becomes $115, with $15 of GST. To find the GST already inside a GST-inclusive price, multiply by 3 and divide by 23: a $115 total contains $15 of GST.

Working out how much GST to add to a price trips people up when quoting jobs, pricing products or checking an invoice, because New Zealand's flat 15% GST is calculated differently depending on which way you are working. To add GST to a GST-exclusive amount, multiply the price by 1.15: a $100 item becomes $115, made up of the original $100 plus $15 of GST. Going the other way is trickier, because you cannot simply take 15% off a GST-inclusive total, since that percentage was worked out on the smaller exclusive figure, not the final one. Instead, to find the GST already sitting inside a GST-inclusive price, multiply the total by 3 and divide by 23, or equivalently by 15/115. A $115 GST-inclusive total contains exactly $15 of GST, because $15 is 3/23 of $115. This page sets out both directions with worked figures so you can check a quote, invoice or receipt by hand, but to run the maths on your own amount, use the linked GST Calculator to add or remove GST from any figure, the GST quick reference table for common price points, or the Reverse GST Calculator to pull the GST component out of a GST-inclusive total. These figures use the current New Zealand GST rate and are indicative only, a guide rather than a substitute for your accounting software or accountant.

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Indicative only, not financial advice. Uses current New Zealand rates for 2026/27. Last reviewed 2026-08-31. See also financial literacy NZ.