2023 GST Adjustment Examples: Credit Notes and Reverse Charge

Key steps and distinctions

For a S$1,000 service invoiced in December 2022, fully paid in January 2023 and performed S$200 before and S$800 after the change, the example adjusts S$800 to 8%. It issues an S$856 credit note and S$864 replacement invoice, giving an S$8 net output-tax increase. If only S$500 payment was after the change while S$800 of work was after it, the lower post-change value is S$500: credit S$535, reinvoice S$540 and increase tax by S$5. The affected tax invoice is adjusted by 15 January 2023 under the stated rule; non-tax invoices follow the specified normal business practice. Additional output tax arises by the earliest new invoice, payment or 15 January. Reverse-charge examples distinguish an election for wholly pre-change services invoiced later from a compulsory adjustment of an old invoice covering later performance. The latter S$700 post-change portion creates S$7 extra tax, accounted at the earlier payment or transitional deadline. Apply each example’s facts and keep performance and payment evidence; do not adjust all 2023 transactions by one percentage point without the required timeline analysis.