Verify a GST-Registered Supplier Before You Pay

Why checking a supplier GST registration matters before you pay

When a Singapore vendor adds 9% GST to a quote or invoice, that line item is a claim about the vendor tax status, not just arithmetic. Only a business that holds a current Goods and Services Tax registration with the Inland Revenue Authority of Singapore may charge and collect GST. A buyer who pays GST to a vendor that is not registered cannot recover that amount as input tax, so the 9% becomes a dead cost instead of a pass-through. On repeat purchases and on renovation, maintenance, logistics, or consultancy contracts, that leakage compounds across every invoice.

ACRA incorporation and IRAS GST registration are two separate registers, and buyers often confuse them. A vendor can hold a live UEN and still sit outside the GST net, because registration is compulsory only once taxable turnover exceeds S$1 million, tested against both past turnover and expected turnover. The latest ACRA register snapshot (data.gov.sg, monthly) counts 624,271 live companies within 2,124,508 total entities, with 523,699 struck-off records in 2025, which shows how large the company population is compared with the subset that must charge GST. A company search that returns a live entity tells you the vendor exists. It tells you nothing about GST.

Verification also protects your own compliance position. IRAS expects GST-registered buyers to hold valid tax invoices before claiming input tax, and a claim built on a defective GST charge can be denied on review. Checking the register before you pay, and keeping the evidence, turns a short search into an audit trail that supports every claim you make. The IRAS guidance on when a business may charge GST and the responsibilities of GST-registered businesses describe the other side of the same bargain.

• Whether the vendor is currently GST-registered on the date of your supply, not just today
• Whether the GST registration number printed on the invoice matches the register entry
• Whether the effective date of registration covers your invoice and delivery dates
• Whether the UEN and registered business name match the details you were given

Buyers who run this check through the GST check tool or directly on the IRAS register catch most problems at the quote stage, when a corrected invoice costs nothing and nobody has parted with money.

How to verify a vendor on the IRAS GST register

The authoritative source is the IRAS Search for GST-Registered Businesses, a free public tool that reports whether a business is currently registered and the effective date of registration. Use the vendor UEN wherever possible, because business names can be typed in many variants while the UEN is unique. Before you start, ask the vendor for the exact name shown on the invoice, the UEN, and the GST registration number, exactly as they intend to bill you.

1. Collect the quote or invoice plus the vendor UEN and GST registration number as printed on the document.
2. Open the IRAS GST register search, complete the picture-code check on the search page, and enter the UEN first, then repeat with the business name if the UEN search returns nothing.
3. Read the status line carefully: currently registered, deregistered with a ceased date, or not found.
4. Compare the effective date of registration against your invoice and delivery dates, not just against today.
5. Cross-check the UEN and business name against company records with a Bizfile company search or a UEN check.
6. Save or print the register result as a PDF and file it with the purchase order so the check is provable later.

Interpreting the result matters as much as running it. Currently registered with an effective date on or before your supply date means the vendor was entitled to charge GST on that invoice. A deregistered status with a ceased date before your invoice date means the vendor should not have charged GST. A not-found result usually means the business was never registered, but it can also mean you typed a trading name instead of the registered name, so retry with the UEN before drawing conclusions.

• Status shows deregistered yet the invoice still carries a GST line for a current supply
• GST number on the invoice differs from the number tied to the register entry
• Effective date of registration falls after your invoice or delivery date
• Vendor cannot or will not supply a UEN that matches the invoice name

The registration rules sit behind these statuses. IRAS explains who must register for GST, including the S$1 million taxable turnover test and the 30-day application window, which is why a fast-growing vendor can be legitimately unregistered one quarter and legitimately registered the next. A buyer-side guide to GST registration checks in Singapore walks through the same logic from the buyer perspective.

Tax invoice red flags that point to a GST problem

A GST-registered supplier must issue a proper tax invoice that allows a GST-registered customer to claim input tax. IRAS requires details including the words Tax Invoice, the supplier name, address, UEN and GST registration number, an invoice number and date, a description of the supply, the GST rate, and the total excluding GST with the GST shown separately. The IRAS guidance on invoicing customers lists each required field. When any of these fields is missing or inconsistent, treat the invoice as suspect rather than merely sloppy.

• GST is charged but no GST registration number appears anywhere on the invoice
• The words Tax Invoice are missing and the document is only called an invoice or receipt on a large supply
• The GST rate is shown as anything other than 9% on a standard-rated local supply made now
• The GST maths does not reconcile, so the GST is not 9% of the stated taxable subtotal
• The business name or UEN on the invoice differs from the quote, the contract, or the bank payee name
• Round-number GST appears on every line of a long invoice, which suggests figures were invented rather than computed
• You are pressed to pay the GST portion in cash or to a personal account while the balance goes to the company account
• The GST number on the invoice belongs to a different business when checked against the register

Consider a fictional example. A fictional contractor, Brightline Renovation Services, emails a S$12,000 quote plus S$1,080 GST, which is exactly 9%, so the arithmetic looks clean. But the quote shows no GST registration number, the later invoice carries a different business name, and the IRAS register has no entry for either name or for the UEN supplied. Each clue alone could be an admin error. Together they describe a vendor charging GST it has no right to collect, and a buyer who pays has little prospect of recovering the S$1,080.

Rate and timing deserve their own check. The standard GST rate is 9% for supplies made on or after 1 January 2024, after the staged rise from 7% to 8% in 2023 and then to 9%, as set out in the IRAS GST rate change guidance for business. An invoice dated this year that still applies 7% or 8% to a standard-rated local supply is either using an outdated template or misunderstanding the rules, and either explanation calls for a corrected invoice before payment. For small supplies not exceeding S$1,000 including GST, IRAS allows a simplified tax invoice with fewer details, so a short receipt for a small purchase is not automatically a red flag. Context decides.

Valid tax invoice versus warning-sign invoice

Use the comparison below as a desk checklist when a new vendor invoice lands in your inbox. No single row proves wrongdoing, but anything in the right-hand column should pause payment until the vendor explains or corrects it.

Work through the table from the top rather than cherry-picking the GST line. Identity mismatches in the first two rows are the strongest predictors of a deeper problem, because a vendor that cannot keep its own UEN consistent across documents is either careless about compliance or trading under details that are not its own. Rate and arithmetic errors lower down are more often honest mistakes, especially around the 2023 and 2024 rate changes, and a genuine vendor will usually fix them quickly when asked.

• PDF of the IRAS register result showing status and effective date
• The original quote and the final invoice with matching names and numbers
• Any corrected or credit-note invoices with their own numbers and dates
• A short note of who confirmed the GST number and when

This folder is your input tax defence. If IRAS ever queries a claim, the register printout plus the matching invoice trail shows the claim rested on evidence available at the time, not on trust alone. Buyers can reuse the same discipline inside a pre-deal counterparty check before larger commitments.

What to do when your vendor is not GST-registered

A not-registered result is information, not an accusation. Many legitimate small businesses trade below the S$1 million taxable turnover threshold and must not charge GST, while IRAS also permits voluntary registration below the threshold for businesses that choose to enter the system. Your task as the buyer is to make the paperwork match reality: no registration means no GST line, no GST number on the invoice, and no input tax for you to claim.

1. Tell the vendor plainly that the register shows no current GST registration and ask for a revised invoice without GST.
2. Confirm the total falls by the full GST amount rather than staying sticky at the GST-inclusive figure.
3. If the vendor insists it is registered, ask for the exact registered name and GST number, then re-run the search yourself.
4. For ongoing contracts, add a term that GST applies only while the vendor holds a current GST registration.
5. Re-check the register before each milestone payment on long projects, since status can change mid-contract.

Pricing conversations need care at this point. A vendor that quoted S$10,000 plus GST while unregistered may ask you to pay S$10,900 anyway as a GST-inclusive price. That is a commercial negotiation, not a tax charge, and you should only accept it knowingly, with an invoice that shows no GST and states the plain selling price. What you must not accept is an invoice that still describes part of the payment as GST when the vendor holds no registration, because that document misstates tax and poisons any input tax claim built on it.

• Can you confirm your current GST registration status and effective date in writing?
• Will you reissue this invoice without GST or in the correct simplified format?
• If you registered recently, what is the IRAS effective date, and does it cover this supply?
• Who in your office owns tax invoices so future documents arrive correct the first time?

Pause and escalate when the vendor doubles down. Refusal to correct a false GST charge, invoices issued under shifting business names, or demands to pay tax portions off the books are not admin quirks. Document everything, hold further payments, seek independent advice on the contract position, and consider reporting suspected GST fraud to IRAS, since only IRAS can investigate and act. For higher-value relationships, a structured GST check workflow or a broader legitimacy check on the company keeps the review proportionate to the exposure.

Frequently asked questions about GST-registered suppliers

Short answers to the questions buyers ask most when a GST line looks uncertain. Each answer assumes a standard-rated local supply unless stated otherwise.

What is the current GST rate in Singapore?

The standard rate is 9% for supplies made on or after 1 January 2024, following the increase from 7% to 8% on 1 January 2023 and then to 9%. The IRAS rate change guidance for business confirms the timeline. Quotes and invoices for current standard-rated supplies should therefore show 9%, and any other rate needs an explanation such as zero-rating for exports or a transitional rule before you pay.

How does a buyer check whether a company is GST-registered?

Search the free IRAS register of GST-registered businesses using the vendor UEN, then confirm the status reads currently registered and the effective date falls on or before your supply date. Save the result as a PDF alongside the purchase order. Cross-check the UEN and business name against company records through company profiles or a UEN check so a name mismatch cannot hide behind a valid-looking invoice.

Is the UEN the same as the GST registration number?

No. The UEN identifies the business on the ACRA register, while the GST registration number identifies its IRAS GST account, and a proper tax invoice shows both. A vendor that prints only a UEN and still charges GST has given you an incomplete document. Match both numbers to the register entry, because either one can reveal a borrowed or mistyped identity.

Can a buyer claim GST paid to a vendor that is not registered?

No. Input tax recovery requires a valid tax invoice from a GST-registered supplier for a taxable supply, and an amount described as GST on an invoice from an unregistered vendor is not tax at all. The practical fix is a corrected invoice without GST and a matching price adjustment. Paying the GST line anyway leaves the buyer funding the vendor margin with no claim to offset it.

What if the vendor registered for GST after the invoice date?

GST applies only from the IRAS effective date of registration stated in the approval letter, so a supply made before that date should not carry GST even if the vendor is registered today. Ask for a corrected invoice without GST for the earlier supply and keep the register result showing the effective date. For staged deliveries that straddle the effective date, each stage follows the registration status on its own supply date.

• Run a GST check on every new vendor before the first payment
• Confirm identity with a Bizfile company search when names and numbers diverge
• Revisit the buyer GST registration guide before claiming input tax
• Need the one-minute register search? How to know if a company is GST registered skips straight to the IRAS lookup