You clicked submit on myTax Portal, felt relieved, and then remembered the rental income you forgot, or the relief you claimed twice. It happens more often than you might think, especially in the rush before the IRAS filing deadline. If you need to amend tax return IRAS records, the right route depends mainly on one thing: whether IRAS has already issued your Notice of Assessment (NOA).
This guide walks through both situations for individual taxpayers. It is general information, not tax advice. IRAS processes and time limits can change, so confirm the current steps on the IRAS website before you act.
Why Timing Matters: Before and After the NOA
When you file, IRAS takes your return and later issues an NOA, which is the official bill showing how much tax you owe. That NOA changes what kind of correction you are making.
- Before the NOA: you are still revising your own return. IRAS has not finalised anything yet, so corrections are usually simple.
- After the NOA: you are asking IRAS to change an assessment it has already made. Depending on the situation, that may be an objection, a request to revise the assessment, or a voluntary disclosure.
If you disagree with how IRAS has assessed you, for example over a relief it disallowed, that is a dispute and the process is different. Our guide on how to object to your income tax assessment covers that in detail. This article focuses on fixing your own mistakes.
Revising Your Return on myTax Portal Before Assessment
If you filed electronically and the NOA has not arrived, you can usually correct your return online.
- Log in to myTax Portal with Singpass.
- Go to the individual income tax section and look for the option to view or revise your filed return for the current Year of Assessment (YA). The wording on the portal may change from year to year.
- Make your changes. Add missing income, remove incorrect claims or update relief details.
- Resubmit. IRAS generally takes the latest version you submit as your return.
- Save the new acknowledgement page for your records.
Some points to note:
- Before the filing deadline, revising is typically as easy as filing again. This is the best time to catch errors.
- After the deadline but before the NOA, an online revision option may still be available. If you cannot find it, contact IRAS through its official channels and explain the correction.
- Paper filers may need to write to IRAS with the corrected details instead, since there is no online form to edit.
What to Double-Check Before Resubmitting
Most revisions involve the same handful of items. Before you submit again, check:
- Employment income from every employer, particularly if you changed jobs, since each employer reports separately under the Auto-Inclusion Scheme (AIS).
- Rental income and allowable expenses
- Freelance, commission or platform income
- Reliefs such as those for parents, children, spouse or course fees, and whether another family member is also claiming the same relief
- Donations, which are usually included automatically if the charity has your details
Our list of common income tax filing mistakes is a handy checklist here.
What to Do After Your NOA Is Issued
Once IRAS has issued your NOA, your options depend on what went wrong.
If You Underdeclared Income or Overclaimed Reliefs
If the error means you paid too little tax, tell IRAS promptly. IRAS has a voluntary disclosure approach for taxpayers who come forward on their own to correct errors before IRAS starts an audit or investigation. Coming forward voluntarily is generally treated more favourably than having the error discovered by IRAS. Check the IRAS website for the current conditions and how to make a disclosure.
You will typically need to provide:
- Your tax reference number and the YA affected
- What was wrong and the correct figures
- Supporting documents, such as tenancy agreements or invoices
IRAS will then revise your assessment and issue an updated NOA.
If You Overdeclared Income or Missed a Relief
If you paid too much tax because of your own mistake, you can ask IRAS to revise the assessment. There are time limits for these requests, and the window depends on the type of claim, so check the IRAS website as soon as you notice the error. If IRAS agrees, the overpayment is usually refunded or offset against other tax. Our guide on how to get an income tax refund from IRAS explains how refunds are paid.
If You Disagree With IRAS’s Assessment
If your return was correct but IRAS assessed it differently, that is a disagreement rather than a mistake on your part. Objections must generally be filed within a set period after the NOA date, which is stated on the notice. Follow the objection process instead of trying to revise your return.
Choosing the Right Route
| Your situation | Route | Where to do it |
|---|---|---|
| Error found before the filing deadline | Revise and resubmit your return | myTax Portal |
| Error found after deadline, no NOA yet | Revise online if available, otherwise notify IRAS | myTax Portal or IRAS contact channels |
| NOA issued, you underpaid due to your error | Voluntary disclosure to correct the assessment | IRAS official channels |
| NOA issued, you overpaid due to your error | Request a revision of the assessment within the time limit | myTax Portal or IRAS official channels |
| NOA issued, you disagree with IRAS’s view | File an objection within the stated period | myTax Portal |
Paying While a Correction Is Being Processed
A common question is whether you can hold off paying while IRAS reviews your correction. In general, you should pay the tax on your current NOA by the due date, even while a revision or objection is in progress. If the revised assessment is lower, IRAS will refund or offset the difference. If it is higher, you will receive a new NOA with the additional amount.
Late payment can lead to penalties that are separate from the correction itself. If you pay by GIRO instalments, your plan normally adjusts automatically when the assessment changes.
Tips to Avoid Needing a Revision
- Do not file on the first day just because the form is ready. Wait until you have all documents, such as statements from overseas employers or banks.
- Check pre-filled figures line by line. Pre-filled does not always mean complete.
- Coordinate reliefs with family members. Siblings sometimes both claim the same parent, which can cause a disallowance later.
- Keep records for several years. IRAS may ask for supporting documents after assessment, so keep receipts and agreements organised.
- Update IRAS after life events. Marriage, a new child or a change in residency status can all affect your return.
The Bottom Line
Mistakes on a tax return are usually fixable. Before the NOA, revise your return on myTax Portal. After the NOA, decide whether you are correcting your own error or disputing IRAS’s view, and use the matching route. Act quickly, keep your documents ready, and check the IRAS website for the latest procedures and time limits.
Official sources: IRAS
Further reading: Missed the Income Tax Filing Deadline? What to Do Next · Checking Your Pre-Filled Income on myTax Portal Before You File