GST F7 or Your Next GST F5? How to Correct GST Errors in Singapore (2026)

By Lucas Seah, Founder of Excellence Singapore Group | Last Updated: October 2026

Found a mistake in a GST return you have already filed? You can fix it in your next GST F5 if it passes both of IRAS’s tests. First, the net GST in error in each affected period, added together, must be S$3,000 or less. Second, the other figures must be out by no more than 5% of the supplies declared for each period. Larger errors, and a few special cases, need a GST F7, filed on myTax Portal within 14 days of requesting it. Act quickly, because IRAS says errors corrected within a year of the GST F5 filing deadline attract no penalties.

Short on time? Jump to which route you need.

Key Takeaways

• Use your next GST F5 if the error passes the S$3,000 GST test and the 5% value test; otherwise, file a GST F7.
• Correct errors, or claim back overpaid GST, within five years of the period end.
• A qualifying disclosure within one year of the filing deadline attracts no penalty, and a flat 5% after that; if IRAS finds the error first, the penalty can reach 200%.
• Errors not directly related to the scope of an IRAS query, audit or investigation can still qualify for reduced penalties.

GST F7 or your next GST F5: which do you need?

Use your next GST F5 only if the error passes both tests in IRAS’s administrative concession; otherwise, file a GST F7.

Source: IRAS, correcting errors made in GST return (GST F7), October 2026.

The two tests, explained

Test 1, the S$3,000 GST test. For each affected period, take the extra output tax you owe (Box 6) minus the extra input tax you can now claim (Box 7). Added together across every affected period, with an overpaid period counting the same as an underpaid one, the total must be S$3,000 or less. The limit was S$1,500 until the end of 2023, so any guide still quoting S$1,500 is out of date.

Test 2, the 5% value test. For each period separately, add up the errors in the value boxes (sales, purchases and the other amounts, but not the GST in Boxes 6 and 7 or a pre-registration claim in Box 12). The total must be no more than 5% of the total supplies declared in Box 4, or of taxable purchases (Box 5) if there were no supplies.

Both tests must be met. The concession changes how you correct, not the penalty rules.

How IRAS’s calculator counts errors

IRAS’s GST F7 calculator (Excel file) runs both tests. Three of its rules catch people out:

• GST errors net off only within a period. Each period’s net GST error then counts in full, whichever way it goes, and the periods are added together, so an overpaid quarter does not cancel out an underpaid one.
• Value errors add up, whichever way they go, so a sale wrongly zero-rated counts twice, once out of Box 2 and again into Box 1.
• The 5% value test is per period, against Box 4 as originally filed.

Worked examples: five errors through both tests

A small GST amount does not guarantee a pass. The 5% value test counts the values, not the tax, and a wrong zero-rating counts twice, so it can fail even when the GST involved is under S$3,000 (example B). The illustrative examples use errors IRAS lists as commonly made, plus the mirror image of B, at 9% GST with quarterly returns.

Swipe sideways to see the full table →

Illustrative figures. Each example assumes the GST is added to the price and recovered from the customer. If it cannot be, IRAS treats the price as including GST (9/109 of it): S$2,477 in B, S$3,303 in C and S$1,503 net in D, which changes none of the results. Sources: IRAS GST F7 page, calculator, common errors and GST General Guide para 5.5.4.

Which GST errors need no correction at all?

IRAS’s GST F7 page lists a few errors that need no GST F7, such as a wrong revenue figure in Box 13, rounding differences and abbreviated company names. An honest error more than five years old needs none either.

Source: IRAS, correcting errors made in GST return (GST F7), FAQs 5 to 14, October 2026.

The five-year cut-off. Once five years from the end of the period have passed, IRAS’s e-Tax Guide on preparing GST returns says no GST F7 is needed. That protects honest mistakes only, because for fraud or wilful default, section 45 of the GST Act lets IRAS assess at any time.

How do you file a GST F7 on myTax Portal?

Request the form, then e-file it within 14 days. Any Preparer or Approver for the business can request it (e-Tax Guide, paragraph 4.2.12). Following IRAS’s F7 page:

1. On myTax Portal, select GST, then File GST Return/Edit Past Return.
2. Under Request for GST F7, select Submit Request.
3. Enter the period’s start and end dates, select Proceed twice, then E-File.

Work out the figures first, because an F7 not submitted within 14 days is deleted. Requested one by mistake? Do nothing; it lapses after 14 days. The F7 replaces the original return, so enter revised totals for every box from 1 to 17, not just the adjustment, and describe the error without special characters such as $, % or colons.

Errors in several periods: one GST F7 per period, or one per year

You can file a GST F7 for each affected period, or consolidate a year’s errors into one GST F7 for the last period of the year, or the last with an error. In IRAS’s example, S$4,000 of output tax errors across 2023 go into the October to December 2023 F7, so Box 6 shows the S$5,000 originally declared plus S$4,000, or S$9,000.

After you file: payment and IRAS’s questions

Follow the payment instructions on the acknowledgement page (GIRO payers: keep the deduction limit above the amount). Even within the grace period, additional GST not paid by its due date attracts a 5% late payment penalty. IRAS may also follow up with questions, and answering them fully is a condition of the reduced penalty. In one of IRAS’s own examples, an F7 filer who left its queries unanswered despite reminders did not qualify.

How long do you have to correct a GST error?

Five years to correct an error or claim a refund, but one year from the filing deadline for no penalty. IRAS’s Voluntary Disclosure Programme guide counts that year from the original statutory filing deadline, not from any extension, but the Timeline section of its GST F7 page counts it from the end of the period. To be safe, correct within 12 months of the period end.

Sources: IRAS, GST due dates, GST F7 page and VDP e-Tax Guide (January 2026); GST Act s45 and s90.

What GST penalties apply if you correct late, or not at all?

The same error can cost nothing, 5% of the tax, or up to 200% of it if IRAS finds it first. On S$10,000 of GST undercharged:

Sources as linked, read October 2026.

The business stays responsible for its GST filing and payment even if its tax agent fails to act, as IRAS points out. If IRAS has written first, see our guide to IRAS letters and audits. To dispute a GST assessment, object in writing within 30 days. Our Notice of Assessment guide explains how to read the notice.

Can the 5% late payment penalty be waived?

Possibly, through the Appeal Penalty Waiver service on myTax Portal, but IRAS considers an appeal only if all GST returns are filed, the overdue tax is paid in full by the due date in the penalty notice, and no waiver was granted in the past 2 calendar years. Our IRAS penalty waiver guide covers the conditions for each IRAS penalty and how to appeal.

How a GST F7 doubles as a voluntary disclosure

For GST, the F7 is your voluntary disclosure, and a qualifying one cuts the penalty to nil or a flat 5%. The GST 5% is a one-off figure, unlike income tax’s 5% for each year late. Under IRAS’s Voluntary Disclosure Programme, the disclosure must be accurate and complete, and made before IRAS queries you or notifies you of an audit or investigation. You must then cooperate fully and pay. Repeat disclosures can qualify too, but IRAS then expects adequate and robust controls to stop a recurrence. Our guide to the IRAS Voluntary Disclosure Programme covers the other taxes it applies to.

Already heard from IRAS?

You may still qualify for errors not directly related to the scope of the query, audit or investigation. IRAS’s e-Tax Guide on the programme (January 2026) gives two GST examples that qualified: an F7 for output tax errors during an input tax audit of the same period, and an F7 for input tax errors a previous audit had missed. Disclose errors within the scope at the earliest possible time anyway. Our guide to IRAS letters covers voluntary disclosure once IRAS has written.

How do you claim back GST you overpaid?

File a GST F7 within five years of the end of the period, with every affected period fully quantified, because IRAS treats a refund claim as made only once that is done. Section 90 of the GST Act sets the same five-year limit, so a period two or three years back is still in time. IRAS’s calculator applies the same two tests to an overpayment, so a small one that passes both can be adjusted in your next GST F5 instead.

• Unsure of the treatment? IRAS asks you to write in before filing, describing the issue and breaking down the GST to be refunded for each period.
• Charged customers GST you should not have? Issue credit notes before you claim, and keep them as evidence. Under section 90(2), IRAS can reduce or withhold a refund that would unjustly enrich you, and under section 90(3) it can set a refund off against tax you owe.

Refunds reach a GIRO or PayNow account within 7 days of the credit arising. For a refund shown on a GST F5 (input tax exceeding output tax), IRAS’s refund due date is 1 month after it receives the return for monthly filers and 3 months for quarterly filers. A refund claimed by GST F7 is paid once IRAS is satisfied the GST was overpaid, so allow time for its review. IRAS can also hold a refund back during an audit or if it suspects fraud.

Special cases: pre-registration, deregistration and ASK reviews

Errors in a pre-registration claim or in a final GST F8 always need a GST F7. Errors found in an Assisted Self-help Kit (ASK) review get a longer penalty-free window, and a few problems are disclosed another way, not by an F7.

Pre-registration claims

These are claimed only in your first GST return (in Box 7, with the amount declared in Box 12), and the concession excludes Box 12, so errors need a GST F7 for that first return.

After you deregister (GST F8)

Errors in your final GST F8 need a GST F7, as there is no next GST F5 to adjust in. Keep the business bank account open until any refund arrives, because IRAS refunds only to the business, not its directors or partners.

Errors found in an ASK review

For errors an ASK Annual Review uncovers, IRAS waives the 5% late payment penalty if you disclose them within one year of the statutory filing date of the last return of the financial year reviewed, provided the voluntary disclosure conditions are met. For a financial year ending 31 December 2025, that means by 31 January 2027. ASK is also compulsory for certain GST scheme applications and renewals. Our Major Exporter Scheme guide explains what the review involves and who can certify it.

Problems you disclose another way

• A return never filed. File the overdue GST F5 or F8, within five years of the period end, to replace IRAS’s estimated assessment.
• Registering late. Register on myTax Portal. IRAS is prepared not to penalise late registrants who come forward (see our GST registration threshold guide).
• GST collected while unregistered, or Missing Trader Fraud input tax. Disclose it by email to gst@iras.gov.sg.

How do you stop the same error coming back?

Fix the cause as well as the return. IRAS’s commonly made errors, such as GST claimed on motor car or private expenses, zero-rating for overseas customers, and missed GST on gifts over S$200 or on business assets sold, each start in the books, as a wrong tax code or a sale or gift booked with no GST.

The fixes are routine. Set the tax codes up properly (our accounting software comparison covers the main options), reconcile GST to the ledger every quarter, keep records for at least five years, and recheck the codes if you move to InvoiceNow. IRAS’s ASK Annual Review is its own framework for a self-review of your GST returns. Our guides to accounting compliance, the monthly compliance checklist and common tax mistakes for SMEs cover the rest.

How we help with GST corrections

Excellence Singapore Group’s tax team, which brings accreditation from the Singapore Chartered Tax Professionals (SCTP) in both income tax and GST, handles GST returns and corrections, including GST F7 filings, and IRAS letters, audits and voluntary disclosures. When you find an error:

1. Send us the return and what looks wrong, before you file anything.
2. We confirm it really is an error and, where the GST treatment is a judgement call, whether to ask IRAS before filing.
3. We quantify it and choose the route, running IRAS’s two tests across every affected period. A disclosure only qualifies for reduced penalties if it is accurate and complete, so we get the figures right before anything is filed.
4. We prepare, file and time it, with a working file kept for audit, aiming to stay inside the penalty-free window. If IRAS has already written, we find the errors outside its scope that can still be disclosed voluntarily, and handle its questions.
5. We fix the cause, with the right tax codes, quarterly GST reconciliations, and alignment with your corporate tax computation and accounts.

Fees for GST corrections are quoted after we review the return and the error. If you have not found anything yet but want to check before IRAS does, ask us for a GST review, including IRAS’s ASK Annual Review, where errors found get a longer penalty-free window.

Frequently Asked Questions

What is a GST F7 form?

The GST F7 is IRAS’s form for correcting errors in a GST return already filed, whether a GST F5, an earlier GST F7 or a final GST F8. It mirrors the GST F5, with corrected figures for every box, and replaces the earlier return. You file it online.

Can I fix a GST error in my next GST F5?

Yes, if the net GST in error, added up across all the affected periods, is S$3,000 or less and the errors in the other boxes, except Boxes 6, 7 and 12, are within 5% of Box 4 in each period. Otherwise, or for pre-registration claim or GST F8 errors, file a GST F7.

What is the GST F7 due date?

Submit a GST F7 within 14 days of requesting it, or it is deleted. Errors must be corrected within five years of the end of the accounting period, and within one year of the original filing deadline for no penalty; acting within 12 months of the period end is safest.

Is there a penalty for filing a GST F7?

Not for a qualifying voluntary disclosure made within one year of the original filing deadline, if the extra GST is paid on time. After that, a qualifying disclosure attracts a flat 5% of the GST undercharged. Errors that IRAS finds first can attract up to 200% of the tax.

Can I claim a GST refund after 2 years?

Yes. Overpaid GST, such as output tax over-accounted or input tax not claimed, can be claimed by GST F7 within five years of the end of the accounting period, once every affected period is fully quantified. IRAS may reduce a refund that would unjustly enrich you.

Can I file a GST F7 during an IRAS audit?

Yes. Errors not directly related to the scope of IRAS’s query, audit or investigation can still qualify for reduced penalties, such as output tax errors disclosed during an input tax audit. Errors directly related to its scope do not qualify, but IRAS asks you to disclose them at the earliest possible time.

Found a GST error? Fix it before IRAS does

A qualifying disclosure within one year of the original filing deadline carries no penalty, and that clock is already running. If you have found an error, talk to us and send us the return and what you found; we will tell you which route applies and what the correction involves.