It is late October and your team is preparing the GST return for July to September. While checking the figures, someone notices that a S$20,000 sales invoice from the previous quarter was never included. The return for that quarter has already been filed and paid.
This happens more often than most business owners expect, and it is fixable. You cannot edit a GST return after submitting it, but IRAS gives you two ways to correct it: adjust the error in your next GST return, or file a GST F7 (Disclosure of Errors on GST Return). Which route applies depends on the size of the error. When you act matters just as much, because errors you disclose voluntarily and early are generally not penalised.
This guide explains both routes, the two tests that decide between them, worked examples, the GST F7 filing steps on myTax Portal and the penalties to be aware of. Figures are current as of 21 October 2026.
Key Takeaways
GST F7 is the form you use to correct a GST return you have already filed, when the error is too large to adjust in your next return. It is formally called the Disclosure of Errors on GST Return, and it supersedes the original return for that accounting period.
If you are unsure how your accounting periods are set, our guide to GST accounting periods explains the options.
Not every discrepancy requires action. According to the IRAS e-Tax Guide on preparing GST returns, an error that only affects Box 13 (revenue) does not need adjusting; you simply report the correct revenue going forward. Minor differences such as rounding generally do not need correcting either. Errors more than five years old fall outside the correction window, which we explain further below.
Yes, if the error passes both of IRAS's tests. This concession saves you filing a separate form, but it only covers errors in Boxes 1 to 7 of the GST F5. Errors in other boxes need a GST F7 for the affected period.
Add up the GST errors across every affected accounting period. The net GST error is the output tax error minus the input tax error. If the total is S$3,000 or less, the error passes this test.
For each affected period, add up the errors in the value boxes (such as standard-rated supplies in Box 1, zero-rated supplies in Box 2 and taxable purchases in Box 5). The total must be no more than 5% of the total supplies declared in Box 4 for that period. If you made no supplies in that period, the test uses taxable purchases in Box 5 instead.
If the error passes both tests, include the correction in the relevant boxes of your next GST F5. If it fails either test, file a GST F7. These conditions are set out in the IRAS e-Tax Guide on preparing GST returns.
The net GST threshold was S$1,500 for many years. IRAS raised it to S$3,000 for returns falling due after 1 January 2024, following the GST rate increase to 9%. Many older articles and internal checklists still quote S$1,500, so check which figure your team is using.
Some errors must go through a GST F7, whatever their size:
The size of the error decides the route. The three examples below assume a quarterly filer charging GST at 9%.
A company finds that a standard-rated invoice of S$20,000 was left out of its April to June return. Box 4 for that quarter shows total supplies of S$600,000.
Both tests pass, so the company adds S$20,000 to Box 1 and S$1,800 to Box 6 in its July to September return, and pays the extra GST with that return.
A company claimed S$3,600 of input tax on S$40,000 of running costs for a company passenger car. Input tax on such expenses is generally disallowed. Our guide to claiming input tax correctly explains which expenses qualify.
Test 1 fails, so the company must file a GST F7 for that period, whatever the result of Test 2.
A company treated a S$30,000 service as zero-rated, but the service did not meet the conditions for zero-rating. Box 4 shows total supplies of S$400,000.
Test 2 fails, so a GST F7 is required. This example shows why a single misclassification can count twice. Our guide to zero-rating rules explains the documents IRAS expects.
Most GST errors are routine, not deliberate. They usually come from how expenses are classified or how documents are kept. In FY2023/2024, IRAS completed 2,521 GST audits and recovered S$162 million in taxes and penalties, according to an EY Singapore tax alert on GST audit focus areas. The errors IRAS sees most often include:
A GST F7 is requested and e-filed on myTax Portal by a user with the Preparer or Approver role for GST. The process takes five steps.
Before requesting the form, recalculate the full return for the affected period. A GST F7 replaces the original return, so you need the correct total for every box, not only the boxes with errors.
Log in to myTax Portal, select GST, then File GST Return/Edit Past Return, and submit a request for GST F7 for the relevant accounting period.
Once requested, the GST F7 must be e-filed within 14 days. If it is not filed in time, the request lapses and you will need to submit a new one.
Use the description field to explain what went wrong, which periods are affected and how the error was found. A clear explanation reduces follow-up questions from IRAS.
If the GST F7 shows more GST payable, the amount is treated as due on the original filing due date for that period, so pay it promptly. If it shows an overpayment, IRAS will process the refund once it is satisfied with the claim.
Do not enter only the difference. If the original return showed S$5,000 in Box 6 and S$4,000 was missed, the GST F7 should show S$9,000 in Box 6. Where several periods in the same year are affected, the IRAS e-Tax Guide allows you to consolidate the errors into one GST F7 for the last accounting period of that year.
Usually not, if you disclose the error yourself and act within a year. Under the IRAS Voluntary Disclosure Programme, penalties depend on when and how the error comes to light.
If you disclose a qualifying error within one year of the statutory filing due date of the return, IRAS generally imposes no penalty. The IRAS e-Tax Guide on the Voluntary Disclosure Programme (Thirteenth Edition, January 2026) sets out the conditions. The disclosure must be:
A qualifying disclosure made after the one-year grace period attracts a flat penalty of 5% of the tax undercharged.
Errors that IRAS discovers through a query or audit can attract penalties of up to 200% of the tax undercharged. Cases involving wilful intent to evade tax are treated separately and more seriously. Our guide on what happens in an IRAS GST audit explains the process.
If additional GST is not paid by its due date, a 5% late payment penalty applies. If the tax remains unpaid 60 days after that penalty, a further 2% per completed month is added, capped at 50% of the unpaid tax.
Up to five years from the end of the accounting period in which the error occurred. For example, an error in the period ending 31 December 2023 must be corrected by 31 December 2028. After five years, you no longer need to file a GST F7 for that period. In practice, correcting an error as soon as you find it keeps you within the penalty-free window and avoids the error carrying into later returns.
You can also use a GST F7 to recover GST you overpaid, for example where you missed input tax you were entitled to claim. If the overpayment came from charging customers too much GST, issue credit notes to those customers before claiming the refund and keep them as evidence.
IRAS may ask for a breakdown of the overpaid GST by period. It can also withhold or reduce a refund where repaying it would unjustly enrich the business, or set it off against other tax owed.
A short review before each filing catches most errors while they are still easy to fix. Practical habits include:
GST is one of several year-round obligations. Our annual compliance guide puts the key deadlines in one place.
No. Once a GST F5 is submitted, it cannot be edited. Errors are corrected either in your next GST return, if they pass both tests, or by filing a GST F7.
In total. The S$3,000 test looks at the net GST error added up across all affected accounting periods. The 5% test, by contrast, is applied to each period separately.
Generally, a GST F7 is filed for each affected period. However, errors from accounting periods within the same year can be consolidated into one GST F7 for the last accounting period of that year.
IRAS may follow up with questions about the errors you disclose, so keep your workings and supporting documents ready. Disclosing errors voluntarily is treated more favourably than having IRAS find them, both in penalties and in how the matter is handled.
Errors that fall within the scope of an IRAS query, audit or investigation already underway do not qualify for the reduced penalties under the Voluntary Disclosure Programme. Errors outside that scope may still qualify if disclosed voluntarily, accurately and completely.
Yes, provided they have been authorised on myTax Portal with the Preparer or Approver role for your company's GST. The responsibility for the accuracy of the return still rests with the business.
Finding an error in a filed GST return is stressful, but it is usually manageable when it is handled early and methodically. ATHR's accounting and tax team supports Singapore businesses with:
Every client works with a dedicated Key Account Manager who knows your business and answers questions before deadlines arrive, not after.
If you have spotted an error, or simply want a second look at your last return before the next one is due, speak with ATHR about your GST filing.
This guide is for general information only and reflects IRAS guidance available as of 21 October 2026. It does not constitute tax, legal or accounting advice. GST rules, thresholds and penalty treatment may change, and the correct approach depends on your business's specific facts. Please refer to the latest IRAS publications or consult a qualified professional before acting on any information in this article. ATHR accepts no liability for any loss arising from reliance on this content.
The ATHR Content Team is a group of professional writers from Singapore and the Philippines, committed to delivering informative, practical, and engaging content for business owners across Southeast Asia.
