GST and tax

Tax name, rate, the tax invoice title and what your registration number is called are all configurable per company, in Settings → Company Profile → Tax Settings. Picking a country there fills the four fields in with that country's usual values (UK VAT 20% on a “VAT Invoice” showing a “VAT No.”, NZ GST 15% showing an NZBN) and then leaves every one of them editable. New companies start on the Australian defaults — 10% GST, titled “Tax Invoice”, showing your ABN — though the tax-invoice eligibility rules underneath are still the ATO's.

Currency sits with those fields and is prefilled by the same country picker (New Zealand → NZD, the UK → GBP, Ireland → EUR). It is the code printed on your receipts, invoices and job cards — the footer that used to say “All prices in AUD” on every tenant's paperwork now says whatever you trade in. Amounts are never converted: a document is priced in one currency, and an invoice keeps the currency it was issued in even if you change the setting afterwards.

Tax is inclusive in the price shown, not a US-style sales tax added at checkout. A company that is not registered charges none at all — the effective rate is zero, not a hidden default. And because an issued invoice freezes the wording it was sent with, changing these settings later never rewrites an invoice already sent.

Discounts reduce the taxable base

An invoice-level discount reduces the consideration, so it reduces what GST is charged on. The discount is pro-rated across the lines, and GST is charged on the discounted net.

This matters for BAS. Charging GST on the full line total and subtracting the discount afterwards over-declares GST and produces a document that does not add up. Every invoice satisfies:

subtotal − discount + tax = total

Turning GST registration off

Registration status is read when the invoice is built. Figures on screen match the saved invoice, so an invoice cannot show one set of numbers and store another.