Singapore GST: the complete guide for 2026

Singapore GST is administratively lighter than the UK VAT or Australian BAS regimes, but the rule set has more depth than the headline 9% rate suggests. A two-step rate move in 2023 and 2024 still produces dated receipts at the old rate. The S$1,000 threshold between simplified and full tax invoices flips a set of completeness requirements bookkeepers regularly miss. Regulations 26 and 27 of the GST (General) Regulations list expense categories on which input tax cannot be claimed even when the supporting invoice is perfect. Overseas Vendor Registration and reverse charge run in parallel; the right one depends on facts that do not appear on the invoice. This guide covers what every Singapore SMB owner and bookkeeper needs to know in 2026: the rate, the threshold, the filing cycle, the tax-invoice rules, the IRAS Reg 26 / 27 blocked input tax list, the cross-border rules, and the specific edge cases ExpenseFlow handles at capture so they never reach the F5. Every figure, deadline, and regulation in this guide is referenced to an official IRAS publication or other Singapore Government source; full URLs appear in the Sources section at the end.

What GST is and how it works in Singapore

GST is Singapore’s broad-based consumption tax, charged at 9% on most goods and services consumed in Singapore ^[1] . GST-registered businesses collect GST from their customers, pay GST to their suppliers, and remit the net amount to IRAS through the F5 GST return. Singapore Customs collects GST at the border on imported goods, and the OVR regime catches B2C cross-border supplies of remote services and low-value goods from overseas vendors.

There are four categories of supply ^{[1] [3]} :

The distinction between zero-rated and exempt is the one that catches new businesses out. Both show no GST on the invoice. A zero-rated supplier (an exporter) can still recover the GST it paid on its inputs; an exempt supplier (financial-services firms, residential landlords) cannot. Same arithmetic on the customer side, opposite consequences on the supplier side.

The S$1 million registration threshold

You must register for GST when your taxable turnover reaches S$1 million ^[2] . Two tests apply and they sit on different timelines.

The retrospective test looks at the calendar year, 1 January to 31 December. If your taxable turnover for that calendar year exceeded S$1 million, you must apply to register between 1 January and 30 January of the following year, and you are registered with effect from 1 March. A carve-out: if you crossed S$1 million during the calendar year but do not reasonably expect to be above S$1 million in the next 12 months, you can wait until year-end and register on the retrospective basis ^[2] .

The prospective test fires at any point in the year when you can reasonably expect taxable turnover in the next 12 months to exceed S$1 million, typically because a signed contract pushes the forward-looking total over the line. You must apply within 30 days of the date of forecast. Until 30 June 2025, prospective registrants had to start charging GST from the 31st day after the forecast. From 1 July 2025, the Second Minister of Finance announced a two-month grace period: businesses with a prospective liability on or after that date are registered two months from the forecast ^[2] .

Voluntary registration is available below the threshold; once registered voluntarily, you must stay registered for at least 2 years. Taxable turnover excludes exempt supplies, out-of-scope supplies, and one-off sales of capital assets. The retrospective trigger is on a calendar-year basis, not your accounting year, which is one of the most common mis-tracks at year-end.

The F5 filing cycle

The F5 is filed through myTax Portal. The default cycle is quarterly; the four standard quarters and their filing and payment due dates are ^[4] :

Businesses on GIRO have payment deducted on the 15th of the month after the filing due date ^[4] . Monthly filing is elective and is sometimes used by net-refund businesses (exporters, businesses with heavy zero-rated supplies) that want to recover input tax sooner. There is no annual cycle; Special Accounting Periods exist for businesses whose financial year does not align with the calendar quarter, with the same one-month-after-period-end deadline ^[4] .

IRAS does not generally grant filing extensions outside a narrow list of acceptable reasons (a first-time GST registrant’s first F5, system breakdown with supporting evidence, key accounting personnel on long medical leave, documented company restructuring, software failure on a seamless-filing API submission) ^[4] . Routine reasons (year-end accounting close, a director travelling overseas, new accounting personnel coming up to speed) are not accepted ^[4] . A nil F5 is still due if you are registered but had no activity in the period.

Tax invoices: the S$1,000 line

A full tax invoice is required for standard-rated supplies between GST-registered businesses and must contain twelve specified fields ^[3] :

1. The words “Tax Invoice”
2. Supplier’s name and address
3. Supplier’s GST registration number
4. Invoice date
5. Invoice identifying number
6. Customer’s name
7. Customer’s address
8. Description of goods or services
9. GST rate
10. Total amount payable excluding GST
11. Total GST
12. Total amount payable including GST

For mixed supplies (some standard-rated, some zero-rated, some exempt on the same invoice), the gross amount for each type must be shown separately ^[3] . The tax invoice must be issued within 30 days from the time of supply ^[3] .

A simplified tax invoice is permitted where the total amount payable (including GST) does not exceed S$1,000. It needs only six fields ^[3] : supplier name, address, and GST number; date; invoice number; description; total including GST; and a statement similar to “price payable includes GST”. Customer name and address, per-line quantity, and a separately stated GST amount are not required. Receipts from restaurants, taxis, and retail under S$1,000 generally function as simplified tax invoices.

On the GST registration number ^[3] : ACRA-registered entities normally use a 9-digit Unique Entity Number where the UEN doubles as the GST number, written as 123456789A (the trailing letter is a check character). Entities without a UEN (foreign-incorporated entities, certain unincorporated bodies) get an M-series number, written as M21234567K or M2-1234567-K. ExpenseFlow’s GST-number validator accepts both formats and flags numbers that do not match.

Peppol invoices submitted via InvoiceNow are accepted by IRAS as valid for input tax claims without the “Tax Invoice” wording, provided the other Regulation 11 fields are present.

IRAS Reg 26 and Reg 27: the disallowed input tax list

The detail in this section is what sets the Singapore rule set apart from most other GST regimes. Regulations 26 and 27 of the GST (General) Regulations list specific categories of expense on which input tax cannot be claimed, even when the supporting tax invoice is otherwise perfectly valid ^[5] . The list is structured: some categories have no statutory carve-out (the claim is disallowed, full stop); others have narrow carve-outs that depend on facts the invoice does not show (the bookkeeper must verify the basis before claiming).

The hard-block categories, where input tax cannot be recovered regardless of business purpose:

The narrower set, where carve-outs exist but cannot be read off the document:

Input-tax errors are among the most common findings in IRAS GST audits, with thousands of businesses sampled each year and material penalties on average per audited business ^[5] . Compounding the error across hundreds of invoices a quarter is the avoidable cost.

Edge cases ExpenseFlow handles at capture

Most Singapore GST errors are repetitive and obvious in hindsight. They scale badly across hundreds of bills a quarter and the cost of catching them at the F5 is much higher than catching them when the receipt is first scanned. ExpenseFlow’s compliance engine encodes the Singapore-specific rules that bookkeepers flag most often, supported by an AI reviewer that reads an IRAS-derived knowledge base for the judgment-heavy cases.

Alongside these deterministic rules, every captured document passes through an AI review that reads an IRAS-derived knowledge base. It handles the judgment-heavy cases that resist fixed rules: a foreign supplier coded as if it were domestic (and the reverse); a borderline imported-service scenario that falls between OVR and reverse charge depending on whether the vendor is OVR-registered; a fixed-asset purchase posted to an expense code; an invoice whose date sits outside the input-tax claim window; a document addressed to a different legal entity than the practice’s client; a Customer Accounting tax invoice for prescribed goods (mobile phones, memory cards, off-the-shelf software) above S$10,000 where the buyer must self-account for the GST. Each finding carries an explanation and, where applicable, a suggested replacement tax code drawn from the practice’s actual platform chart.

The split is intentional: thresholds, format, math, and the other rule-shaped things stay deterministic; only cases that need semantic judgment go through the AI path. The bill or expense arriving in Xero or QuickBooks Online is already coded, already rate-checked, and already screened against the Singapore-specific edge cases.

Cross-border: OVR, reverse charge, and imported goods

Singapore has three cross-border patterns and the right one depends on what is being supplied, who is buying, and whether the overseas vendor is registered for SG GST.

Imported goods. Physical goods crossing the Singapore border are subject to 9% import GST collected by Singapore Customs at the point of import, charged on the CIF value plus customs duty plus incidental charges. The supporting document for an input-tax claim is the Singapore Customs GST IN-PERMIT filed via TradeNet by the freight forwarder or declaring agent, not the foreign supplier’s invoice. A S$400 GST relief threshold applies to parcel-post imports of non-dutiable goods; above it, the entire value is subject to GST, not just the excess.

Overseas Vendor Registration (OVR). Overseas businesses with global annual turnover above S$1 million and B2C supplies of remote services or low-value goods to Singapore above S$100,000 a year must register for GST in Singapore under a simplified pay-only regime and charge SG GST on those B2C supplies ^[8] . The regime started on 1 January 2020 for digital remote services and expanded on 1 January 2023 to low-value goods (CIF up to S$400) and non-digital B2C remote services. If you are GST-registered in Singapore and buying from an overseas supplier, supply your GST number at signup to avoid being charged OVR GST on top; OVR GST charged to a registered SG business is not recoverable as input tax under the simplified-framework rules.

Reverse charge. When a GST-registered Singapore business buys services from a foreign supplier that is not registered for SG GST, and the buyer is not entitled to full input tax recovery, the buyer self-accounts for GST: output tax in Box 1 of the F5 and the corresponding input tax in Box 7 to the extent the supply is attributable to taxable activity ^[7] . The regime has applied to B2B imports of services since 1 January 2020. From 1 January 2023, the scope expanded to imported low-value goods (under the same S$400 CIF threshold) and B2C non-digital remote services. Reverse charge typically nets to zero on the F5 for a fully taxable buyer; partially exempt buyers (financial-services firms, residential landlords) pay net output tax to the extent the imported supply attributes to exempt activity.

Records, retention, and the audit trail

You must keep GST records for at least 5 years from the end of the relevant accounting period ^[9] . Records include sales and purchase invoices, tax invoices supporting input-tax claims, import permits, F5 copies, the GST account itself, and documents supporting any reverse-charge or OVR treatment. Electronic records are accepted by IRAS without prior approval. Failure to keep records is an offence carrying a fine up to S$5,000 or imprisonment up to 6 months for a first offence ^[9] .

ExpenseFlow stores every captured receipt at original resolution alongside the extracted data, so the audit trail from source document to F5 row is preserved without paper. The Singapore Customs IN-PERMIT, IRAS-issued correspondence, and original loan or insurance documents benefit from being kept in their issued form alongside the digital workflow record.

InvoiceNow: the e-invoicing rollout

InvoiceNow is Singapore’s nationwide e-invoicing network, run on the Peppol standard and managed by IMDA ^[10] . IRAS is phasing in mandatory submission of invoice data via InvoiceNow-Ready Solutions over six years ^[10] :

Peppol invoices without the “Tax Invoice” wording are accepted by IRAS as valid for input tax claims ^[10] , provided the other Regulation 11 fields are present. ExpenseFlow’s tax-invoice completeness check is wired to this carve-out so e-invoices are not flagged for the missing label. The InvoiceNow rollout does not change the underlying GST rules: rate, threshold, tax-invoice fields, Reg 26 / 27 disallowed input tax, reverse charge, and OVR all continue to apply as before. InvoiceNow is a transmission mechanism, not a new regime.

GST and your accounting software

The F5 lives or dies on the integration between your receipt-capture tool and your accounting platform. The data that matters is the tax code, the GST amount, the net and gross amounts, the supplier GST number, the invoice date, and (for partial-exemption businesses) the reverse-charge flag. Lose any of those during the sync and reconciliation becomes a manual reconstruction project.

ExpenseFlow syncs natively with Xero (see the Xero integration page) and QuickBooks Online (see the QuickBooks Online integration page). Both syncs are two-way and continuous. Tax codes are mapped against the live tax-rate list at the platform, including the SG-specific OVR, reverse-charge, and customer-accounting codes; supplier contacts are matched against the contact cache; attachments are uploaded so the document sits on the bill or expense. Xero tracking categories and QuickBooks classes are preserved so the management-reporting splits a practice has set up survive the sync.

Sage and MYOB are on our integrations waitlist; see the Sage roadmap page and the MYOB roadmap page. Until the native integrations ship, Singapore practices on those platforms can forward receipts to ExpenseFlow’s inbound email address and the extraction pipeline runs as normal, with manual export at the end of each period.

ExpenseFlow does not file the F5 itself; the responsibility for submission rests with the practice and the myTax Portal user authorised under Corppass.

Where to go next

This guide is the foundation. The practical, country-specific compliance work happens on the Singapore landing page, which covers ExpenseFlow’s Singapore product surface end to end: IRAS audit trail, integration coverage, pricing, and the specific catches the engine ships with today. The Xero integration page and the QuickBooks Online integration page cover the sync semantics for the two platforms we support natively for Singapore practices.

Pricing for Singapore practices is at /pricing/bookkeepers (multi-client practice plans) and /pricing/business-owners (single-business plans), both billed in USD with GST receipts available where required.

If you are evaluating expense-capture tools for a Singapore practice, the best next step is to join the founding-customer cohort with the platform you are on flagged. We onboard practices in cohorts; the request signal is also how we prioritise the Sage and MYOB integrations on the roadmap.