Tax and GST reports

GST is calculated per line on the discounted net and stored on each invoice, so the tax on a document is a recorded figure rather than one re-derived later.

Whether a document was issued as a tax invoice is recorded on the invoice itself. That stays correct even if your GST registration changes afterwards.

For a period figure, the COGS report and the invoice list both take timezone-correct date ranges. See COGS report.