ERP and accounting software for Singapore: GST, InvoiceNow

Singapore compliance in one view

A Singapore business deals with IRAS for GST and income tax, and with the Accounting and Corporate Regulatory Authority for company filings. GST runs at a single standard rate of 9%, with zero-rating for exports and international services and exemptions for certain financial services and residential property. Registration becomes compulsory at S$1 million of taxable turnover, and many smaller businesses register voluntarily because their business customers claim input tax.

The change to plan for is InvoiceNow. IRAS is phasing in a requirement for GST-registered businesses to send invoice data through InvoiceNow-Ready Solutions on the Peppol network. It already applies to new voluntary registrants, and existing registrants are brought in by size between 2028 and 2031.

• GST: 9% standard rate.
• Registration: compulsory above S$1 million on a retrospective or prospective basis, voluntary below.
• Returns: GST F5 within one month after each accounting period.
• E-invoicing: InvoiceNow requirement phased from 1 November 2025 to 1 April 2031.
• Records: at least five years from the end of the accounting period.

GST rate and registration

The current GST rate in Singapore is 9%, which IRAS lists after a two-step increase from 7% through 8% in 2023. Compulsory registration is tested two ways. On the retrospective basis, a business whose taxable turnover for the calendar year exceeded S$1 million applies between 1 and 30 January of the next year. On the prospective basis, a business that can reasonably expect taxable turnover above S$1 million in the next twelve months applies within 30 days of the forecast date.

IRAS expects evidence for a prospective forecast, such as signed contracts or confirmed purchase orders, and a forecast based only on business plans or sales targets does not trigger registration. For forecasts made on or after 1 July 2025, businesses get a grace period of two months before they must begin charging GST, although the application is still due within 30 days.

Filing GST: the F5 return and penalties

GST-registered businesses e-file the GST F5 return within one month after the end of each prescribed accounting period. The return reports standard-rated, zero-rated and exempt supplies, taxable purchases including imports, output tax and input tax. A late return attracts a penalty of S$200 for every completed month it is outstanding, up to S$10,000 per return, in addition to any estimated assessment.

A finance system must therefore produce the F5 box totals for the exact accounting period, keep zero-rated and exempt supplies apart from standard-rated ones, and let you trace each total back to invoices. IRAS recommends keeping a GST account that summarises output and input tax for each period, which is what a ledger with VAT or GST control accounts gives you.

InvoiceNow: who must comply and when

Under the GST InvoiceNow requirement, GST-registered businesses submit invoice data to IRAS using InvoiceNow-Ready Solutions. The InvoiceNow network is based on the Peppol standard, and IRAS receives a copy of the invoice data through IMDA-accredited Access Point Providers. The data covers transactions reported in the GST return, and it is due by the earlier of the GST return filing date or its due date.

Businesses not yet in scope are encouraged to onboard early. IRAS lists InvoiceNow-Ready Solutions accredited by IMDA, free-of-charge packages, and a S$1,000 GST InvoiceNow Transition Grant for SMEs with annual supplies of S$4 million or less. Onboarding may take as little as three months, and most businesses finish within a year.

• 1 November 2025: companies that registered for GST voluntarily within six months of incorporation.
• 1 April 2026: all businesses applying for voluntary GST registration from that date.
• 1 April 2028: new compulsory registrants, and existing registrants with annual supplies up to S$200,000.
• 1 April 2029: existing registrants with annual supplies up to S$1 million.
• 1 April 2030: existing registrants with annual supplies up to S$4 million.
• 1 April 2031: existing registrants with annual supplies above S$4 million.
• Exempt: overseas entities and businesses liable for GST only through the reverse charge regime.

Records, imports and the GST account

Every business keeps its business and accounting records for at least five years from the end of the accounting period, including sales and purchase invoices, import permits, bank statements and the GST account, and the duty continues after a business stops or deregisters. Failing to keep sufficient records is an offence under the GST Act.

Imports need care. Import GST is paid when goods are cleared into Singapore and claimed back as input tax, unless the goods move into a Zero GST warehouse, where import GST is suspended until the goods leave for the local market. The import value is still reported as a taxable purchase in Box 5, but no input tax is claimed because none was paid.

Cities and regions: where the rules differ

Singapore is a single tax jurisdiction, so GST and income tax apply the same way in the Central Business District, Jurong, Tuas, Woodlands, Changi or Tampines. What differs by place is the customs treatment of goods. Free Trade Zones around the port and Changi Airport, and Zero GST and licensed warehouses, let goods be stored with import GST suspended, which matters for traders and logistics firms in Jurong, Tuas and Changi.

Woodlands is the land gateway to Johor in Malaysia, and businesses that move goods across the Causeway deal with both countries' rules. A Singapore business with a Malaysian branch should keep that branch's tax and stock apart from the Singapore entity, since Malaysia has its own sales tax and e-invoicing regime.

What a finance system must do for a Singapore business

Put the rules together and the requirements are concrete. GST has to be set per invoice line so that standard-rated, zero-rated and exempt items can share an invoice. F5 totals must come out of the ledger for the exact accounting period within a month. Credit notes must reverse GST as well as revenue. Stock held in a Zero GST warehouse needs its own location so its suspended GST is reported correctly. Posted entries must be corrected by reversal, because five-year retention only helps if records cannot be quietly changed.

From the InvoiceNow date that applies to you, the system or a connected solution must also send invoice data through an IMDA-accredited access point. That date is the most important fact to check before choosing software.

How Skyline Nexus ERP handles Singapore requirements

Skyline Nexus ERP lets you set up 9%, zero-rated and exempt tax rates and apply them per invoice line. Sales, purchases, payments and expenses post to the general ledger automatically, credit notes reverse revenue and tax, and the tax report and prefilled return form give you output and input totals for any date range and branch to enter on the GST F5. Inventory is held per location, so a Zero GST warehouse can be its own location, with FIFO costing and stock reports. The audit trail records every change with old and new values.

The gap is InvoiceNow. Skyline Nexus ERP is not an IMDA-accredited InvoiceNow-Ready Solution and has no Peppol access point connection yet. A business that must already comply, such as a new voluntary GST registrant since 1 April 2026, needs an InvoiceNow-Ready Solution today. Skyline Nexus ERP fits businesses below the registration threshold and GST registrants whose InvoiceNow date is still ahead, with Peppol sending being rolled out. Payroll for Singapore, including CPF, is not live, there are no bank feeds, and prices are in US dollars from USD 19 a month for Solo, with a free first month.

Rates, regimes and deadlines in this summary change, and many countries are actively legislating on e-invoicing. This is general information, not tax or legal advice — confirm the current position with the authority named above or with your tax adviser before you rely on it.