Whether you're adding GST to the price or determining it from an inclusive amount, we've got you covered!
To calculate the GST-inclusive price when adding GST:
GST-Inclusive Price = Amount * 1.15
If the price already includes GST, use the fraction method:
GST Amount = (GST-Inclusive Price * 3) / 23
GST-Exclusive Amount = GST-Inclusive Price - GST Amount
Source: https://www.ird.govt.nz/-/media/project/ir/home/documents/forms-and-guides/ir300---ir399/ir375/ir375-2021.pdf, Valid as of 20 Jan 2024