How to Amend a Tax Return Already Filed With the NRS

Filed your Nigerian tax return and found an error? How to amend a return filed with the NRS or State IRS — the process, time limits, penalties, and when to use an objection instead.

You filed your tax return. Then you found the mistake. Maybe your employer issued a corrected annual summary after you submitted. Maybe you discovered a WHT credit note you forgot to include. Maybe you realised your pension was computed on the wrong base, or you claimed an expense twice, or you left an entire income source off the return. The question is not whether mistakes happen — they do, to first-time filers and experienced taxpayers alike. The question is what to do about it.

The Nigeria Tax Administration Act 2025 provides mechanisms for correcting errors on filed returns, but the process, the time limits, and the consequences differ depending on whether you are correcting your own mistake or disputing an assessment raised by the tax authority. This guide covers both — so you know exactly how to fix a return that has already been submitted.

When You Need to Amend a Tax Return

Amendments fall into two broad categories: corrections that reduce your tax (you overpaid) and corrections that increase your tax (you underpaid). The process for handling each is the same — you are correcting an inaccurate return — but the practical implications differ because the tax authority’s response to “I owe you less” is different from its response to “I owe you more.”

Common Reasons for Amendment

• Discovered a missed deduction or relief. You filed without claiming rent relief because you could not find the receipt in time. The receipt has now surfaced. Claiming it reduces your chargeable income and your tax.
• Found a WHT credit note after filing. A client issued a WHT credit note that you did not have when you filed. Including it reduces your tax payable.
• Employer issued a corrected annual summary. Your employer’s original PAYE figures were wrong — they have now reissued the annual tax deduction summary with corrected numbers. Your return no longer matches the employer’s revised Form H1.
• Omitted an income source. You forgot to declare freelance income, rental income, or investment income. Your return understates your total income and your tax.
• Claimed an expense you were not entitled to. You deducted a personal expense as a business cost, or claimed rent relief while receiving employer-provided accommodation. Your return overstates deductions and understates your tax.
• Arithmetic error. A miscalculation in the tax bands, an incorrect pension base, a wrong total — the numbers on the return are simply wrong.
• Change in circumstances. You received a bonus, back pay, or additional income after filing that relates to the same tax year.
• Used the wrong tax bands or obsolete reliefs. You filed using the old PITA bands (7% to 24%) instead of the NTA 2025 bands (0% to 25%), or you applied the abolished CRA deduction.

Regardless of the reason, the principle is the same: a filed return that contains an error should be corrected. An inaccurate return — whether it overstates or understates your liability — creates risk. An understated return invites penalties if the tax authority discovers the error. An overstated return means you paid more than you owe.

Option 1: Self-Amendment (You Correct Your Own Return)

A self-amendment is the simplest route. You identified the error before the tax authority did, and you are voluntarily filing a corrected return. This is the process for most taxpayer-initiated corrections.

How the Process Works

1. Prepare the corrected computation. Recompute your chargeable income and tax liability using the correct figures. Document what changed — which line items are different from the original return and why.
2. Prepare a revised return. Complete a new return form with the corrected figures. Mark it clearly as an amended or revised return. Some State IRS portals have a specific “amendment” or “revised return” function; others require you to submit a new return with a cover letter explaining the correction.
3. Write an explanation letter. Attach a letter addressed to the relevant tax authority (your State IRS for individual PIT returns, or the NRS for CIT returns) explaining the nature of the error, the original figures, the corrected figures, and the reason for the amendment. Be factual and specific — “I omitted rent relief of ₦400,000 because the tenancy agreement was not available at the time of original filing” is better than “I made a mistake.”
4. Attach supporting documents. Include the evidence for the correction — the newly found WHT credit note, the corrected employer summary, the rent receipt, the additional income records, or whatever triggered the amendment.
5. Submit the revised return. File it through the same channel you used for the original — the State IRS portal, the NRS Self-Service Portal at selfservice.nrs.gov.ng, or the physical office. Keep the submission acknowledgement.
6. Pay any additional tax owed (or request a refund/credit). If the correction increases your liability, pay the difference immediately. If it reduces your liability, request a refund or a credit to be applied against your next assessment.

Timing Matters

There is no explicit statutory window in the NTAA 2025 that says “you have X months to self-amend.” However, the practical reality is that the earlier you correct an error, the better the outcome. A self-amendment filed promptly after discovering an error — before the tax authority has raised a revised assessment or audit query — demonstrates good faith and is far more likely to be accepted without penalty.

If the error understated your tax and the tax authority discovers it before you correct it, the situation shifts from a voluntary amendment to an enforcement action — with penalties and interest attached. Amending proactively is always preferable to being caught.

Will You Face Penalties for Self-Amending?

It depends on the nature of the error and the direction of the correction:

• If the amendment increases your tax (you underpaid): You will owe the additional tax plus interest for the period between the original filing date and the date of payment. The interest rate is the prevailing CBN Monetary Policy Rate. Administrative penalties may or may not be applied — the tax authority has discretion, and voluntary corrections are generally treated more leniently than errors discovered during an audit. Paying the additional tax immediately when you file the amendment significantly reduces the risk of penalties.
• If the amendment reduces your tax (you overpaid): There is no penalty for claiming a deduction or credit you missed. You are correcting the return to claim what you were entitled to. The tax authority will either issue a refund or apply the overpayment as a credit against your next liability.

Option 2: Objection to an Assessment (You Dispute the Tax Authority’s Figures)

An objection is a different mechanism from a self-amendment. You use it when the NRS or State IRS has raised an assessment — either a revised assessment after reviewing your filed return, or a best-of-judgement assessment because you did not file at all — and you believe the assessment is wrong.

When the Tax Authority Raises an Assessment

After you file a return, the tax authority may accept it as filed (in which case there is nothing to dispute), or they may review it and issue an amended assessment with a different — usually higher — tax figure. This happens when the tax authority believes your return understates income, overstates deductions, applies incorrect rates, or is otherwise inaccurate.

Assessments can also be raised when a taxpayer has not filed at all. In this case, the tax authority issues a best-of-judgement assessment based on whatever information they have — often resulting in a higher figure than the taxpayer’s actual liability because the authority estimates income conservatively (for them, not for you).

How to File an Objection

1. Act within 30 days. You must file your objection within 30 days of receiving the assessment notice. This is a hard deadline — missing it severely limits your options. Mark the date you received the notice and work backwards.
2. Write a formal notice of objection. Address it to the relevant tax authority (the office that issued the assessment). State clearly that you are objecting to the assessment under the provisions of the NTAA 2025. Include your name, Tax ID, the assessment reference number, the tax year, the assessed amount, and the amount you believe is correct.
3. State the grounds for objection. Explain specifically why the assessment is wrong. “The assessment is too high” is not sufficient. You need to identify what the tax authority got wrong: “The assessment includes ₦2,000,000 in income from [source] which I did not receive” or “The assessment disallowed rent relief of ₦500,000 which I am entitled to — supporting documentation is attached” or “The assessment applies the wrong WHT rate to my consulting income.”
4. Attach supporting evidence. Every ground of objection must be supported by evidence — income records, expense receipts, WHT credit notes, employer summaries, bank statements, or whatever proves your position.
5. Submit the objection. File it with the same tax authority that issued the assessment, through their portal or physically at their office. Keep a copy and obtain an acknowledgement of receipt.

What Happens After You Object

Once the tax authority receives your objection, they review your grounds and supporting evidence. The process typically follows this sequence:

• Review and negotiation. A tax officer reviews your objection and may request additional information or documentation. There is usually a period of back-and-forth where you and the tax authority attempt to reach an agreement on the correct figures. This is where most objections are resolved — the tax authority either accepts your position (fully or partially), or you accept theirs, or you compromise.
• Revised assessment. If the objection results in an agreement, the tax authority issues a revised assessment reflecting the agreed figures. You pay the revised amount, and the matter is closed.
• Unresolved objection. If you and the tax authority cannot agree, the tax authority issues a final determination. At this point, you can either accept their figure or escalate to the Tax Appeal Tribunal.

Do You Have to Pay While the Objection Is Pending?

This is a critical practical question. Filing an objection does not automatically suspend your obligation to pay. The tax authority may require you to pay the amount you accept is due (the undisputed portion) while the objection is being reviewed. For example, if the assessment is ₦3,000,000 but you believe it should be ₦1,800,000, you should pay the ₦1,800,000 immediately and dispute the ₦1,200,000 difference.

Paying the undisputed amount demonstrates good faith and prevents interest and penalties from accumulating on the portion you acknowledge you owe.

Option 3: Appeal to the Tax Appeal Tribunal

If your objection to the tax authority is not resolved to your satisfaction, you can appeal to the Tax Appeal Tribunal (TAT). The TAT is an independent body that adjudicates tax disputes between taxpayers and the tax authority.

When to Appeal

You appeal to the TAT when the tax authority has issued a final determination on your objection and you still disagree with the assessment. The appeal must be filed within 30 days of receiving the tax authority’s final determination.

The 50% Deposit Requirement

To file an appeal with the TAT, you are generally required to deposit 50% of the disputed tax amount (or as directed by the TAT). This deposit requirement exists to deter frivolous appeals — it ensures the taxpayer has genuine grounds for disputing the assessment, not just a desire to delay payment. The deposit is refunded (or credited) if the TAT rules in your favour.

The TAT Process

1. File a notice of appeal with the TAT within 30 days of the tax authority’s final determination
2. Pay the required deposit
3. Both parties (you and the tax authority) submit written statements of facts and arguments
4. The TAT conducts a hearing — you may represent yourself, but legal representation by a tax lawyer or chartered accountant is strongly recommended
5. The TAT issues a decision that is binding on both parties (subject to further appeal to the Federal High Court on points of law)

TAT proceedings are more formal than the objection stage and involve legal arguments, evidence presentation, and cross-examination. This is not a process most individuals should navigate without professional help. If your dispute reaches the TAT, engage a tax lawyer or an experienced tax practitioner.

Practical Scenarios: Which Route Do You Take?

Scenario 1: You Forgot to Claim Rent Relief

You filed your 2026 return in February 2027 without claiming rent relief because you could not locate your tenancy agreement. In April 2027, you find the agreement and rent receipts.

Route: Self-amendment. Prepare a revised return including the ₦500,000 rent relief (or the actual amount, whichever is lower). Attach the tenancy agreement and rent receipts. Submit to your State IRS with a cover letter explaining the correction. Request a refund or credit for the overpaid tax.

Expected outcome: The State IRS accepts the amendment and either issues a refund or applies the credit to your next assessment. No penalties apply — you are claiming a deduction you were entitled to.

Scenario 2: You Discovered Unreported Freelance Income

You filed your 2026 return declaring only your employment income. In June 2027, you realise you forgot to include ₦2,000,000 in freelance consulting fees earned during 2026.

Route: Self-amendment. Prepare a revised return including the freelance income. Compute the additional tax. Collect any WHT credit notes from the consulting clients (5% WHT may have been deducted). File the revised return with payment of the additional tax owed. Include an explanation letter.

Expected outcome: Additional tax is due, plus interest from the original filing date to the date of payment. Voluntary correction reduces the risk of administrative penalties. If you wait and the State IRS discovers the omission first — through employer cross-referencing or client WHT data — the full penalty regime applies.

Scenario 3: The State IRS Raised an Assessment You Disagree With

You filed your 2026 return showing a tax liability of ₦1,200,000. Two months later, the State IRS issues a revised assessment of ₦2,400,000. Their assessment disallows ₦3,000,000 in business expenses you claimed, stating insufficient documentation.

Route: Formal objection within 30 days. Prepare a notice of objection identifying each disallowed expense and attaching the supporting receipts and invoices. Pay the undisputed amount (₦1,200,000) while the objection is reviewed.

Expected outcome: The State IRS reviews your documentation. If the evidence supports the expenses, they issue a revised assessment closer to your original figure. If they maintain the disallowance (perhaps because your receipts are inadequate), you can accept their figure, negotiate, or escalate to the TAT.

Scenario 4: You Received a Best-of-Judgement Assessment Without Filing

You did not file a 2026 return by 31 March 2027. In August 2027, the State IRS issues a best-of-judgement assessment of ₦4,500,000 — far higher than your actual liability of ₦800,000.

Route: File your actual return immediately and object to the best-of-judgement assessment within 30 days. The objection should include your completed return with all supporting documents, demonstrating that your actual liability is ₦800,000. Pay the ₦800,000 plus late filing penalties (₦100,000 for the first month plus ₦50,000 for each subsequent month of default).

Expected outcome: The State IRS replaces the best-of-judgement assessment with an assessment based on your filed return. You pay your actual liability plus late filing penalties and any interest. This is still significantly less than the ₦4,500,000 assessed — but you now have a late filing record.

Scenario 5: Your Employer Corrected Their PAYE Figures

You filed your individual return based on the annual tax deduction summary your employer provided. After filing, your employer discovers a payroll error and issues a corrected summary showing ₦200,000 more in gross pay and ₦36,000 more in PAYE deducted. Your return no longer matches the employer’s revised Form H1.

Route: Self-amendment. File a revised return with the corrected income and PAYE figures, attaching the employer’s corrected summary. The additional ₦36,000 in PAYE was already deducted and remitted by the employer — you are not paying additional tax, just updating the return to reconcile with the employer’s corrected filing.

Expected outcome: Straightforward acceptance. The amendment ensures your individual return and the employer’s Form H1 match — preventing future queries from the State IRS.

Tips for a Smooth Amendment Process

• Amend early. The longer the gap between the original filing and the correction, the more interest accrues on any underpayment and the more suspicion the tax authority may apply to the amendment. Correct errors as soon as you discover them.
• Be transparent. Explain clearly what went wrong and why. A taxpayer who says “I omitted this income because I did not have the records at the time of filing and have now obtained them” is treated differently from one who provides no explanation. Honesty in the amendment letter goes a long way.
• Pay first, dispute later. If the correction increases your tax, pay the additional amount with the amended return. If the tax authority raises an assessment you dispute, pay the undisputed portion immediately. Demonstrating willingness to pay what you owe — even while disputing the rest — is the strongest signal of good faith.
• Keep copies of everything. The original return, the amended return, the explanation letter, all supporting documents, submission acknowledgements, and payment receipts. If the amendment is ever queried, you need a complete paper trail showing what was filed, when, and why.
• Engage a professional for objections and appeals. Self-amendments for simple errors (missed rent relief, found WHT credit note, arithmetic correction) are straightforward enough to handle yourself. Formal objections to assessments — especially large assessments or those involving expense disallowances — benefit from professional representation. A tax practitioner knows the local State IRS procedures, the negotiation norms, and the documentation standards expected. Find one through our Tax Professional Directory.
• Never ignore an assessment. If the NRS or State IRS raises an assessment and you disagree, object within 30 days. If you ignore it, the assessment becomes final and enforceable — even if it was wrong. The 30-day objection window is a hard deadline. Missing it limits your options to exceptional relief, which is difficult to obtain and not guaranteed.

What You Cannot Amend

Not every correction is available through the amendment process:

• Retrospective tax planning. You cannot amend a return to restructure income that has already been earned and declared. If you reported ₦15,000,000 in employment income, you cannot amend the return to reclassify part of it as business income with business expense deductions. The income was what it was — amendments correct errors of fact, not strategic repositioning.
• Time-barred assessments. The tax authority has a statute of limitations for raising assessments (generally six years under the NTAA). Conversely, your ability to amend and claim refunds may be limited by the same window. A correction relating to a tax year from seven or eight years ago is unlikely to be accepted.
• Fictitious deductions. An amendment cannot introduce a deduction for an expense that was not actually incurred or a relief that does not apply to you. Filing a false amended return carries the same penalties as filing a false original return — up to ₦5,000,000 and five years’ imprisonment under the NTAA.

Self-Amendment vs. Objection: Quick Reference

Final Thoughts

An error on a filed tax return is not the end of the world — but it does require action. If you find the mistake yourself, self-amend promptly. If the tax authority finds it, they will issue an assessment, and your 30-day objection window starts ticking. Either way, the worst response is to do nothing. An uncorrected understatement compounds with interest and penalties. An uncorrected overstatement means you are paying more than you owe with no prospect of recovery until you act.

The NRS and State IRS offices handle amended returns routinely — you are not the first person to forget a WHT credit note or miscalculate a tax band. What matters is that the correction is voluntary, documented, and timely. Taxpayers who come forward with honest corrections are treated far more favourably than those who wait to be caught.

Verify your current figures with our PAYE Calculator. Ask a specific question about your amendment to the AI Tax Assistant. For formal objections or TAT proceedings, connect with a qualified tax practitioner through the Tax Professional Directory. For portal access and official guidance, visit selfservice.nrs.gov.ng or nrs.gov.ng.

FAQs About Amending a Nigerian Tax Return

Can I amend a tax return after it has been filed?

Yes. You can file a revised return to correct errors — whether the correction increases or decreases your tax liability. Prepare the corrected computation, attach supporting documentation, write an explanation letter, and submit it to the same tax authority (State IRS or NRS) that received the original return. The earlier you amend, the better the outcome.

Is there a deadline for amending my return?

There is no explicit statutory deadline for self-amendments under the NTAA 2025, but practical limits apply. Amendments should be filed as soon as the error is discovered. The tax authority’s ability to raise assessments is generally limited to six years, and the same window effectively applies to your ability to claim refunds on overpayments. For objections to assessments raised by the tax authority, the deadline is 30 days from receiving the assessment notice.

Will I face penalties for amending my return?

If the amendment reduces your tax (you overpaid), no penalties apply — you are claiming what you were entitled to. If the amendment increases your tax (you underpaid), you will owe interest from the original due date to the date of payment. Administrative penalties may be reduced or waived for voluntary corrections made in good faith, but this is at the tax authority’s discretion. Paying the additional tax immediately with the amended return minimises the penalty risk.

How do I object to an assessment from the NRS or State IRS?

File a formal notice of objection within 30 days of receiving the assessment notice. State your Tax ID, the assessment reference, the assessed amount, and the amount you believe is correct. Explain specifically why the assessment is wrong and attach supporting evidence. Pay the undisputed portion of the tax while the objection is being reviewed.

What is the Tax Appeal Tribunal?

The TAT is an independent body that adjudicates disputes between taxpayers and the tax authority when objections are not resolved. Appeals must be filed within 30 days of the tax authority’s final determination, and a deposit of 50% of the disputed tax is generally required. TAT proceedings involve formal hearings and legal arguments — professional representation is strongly recommended.

What if I received a best-of-judgement assessment because I did not file?

File your actual return immediately and object to the assessment within 30 days. The objection should include your completed return with full supporting documents showing your actual income and tax liability. Pay your actual liability plus late filing penalties. The tax authority should replace the estimated assessment with one based on your filed return — which is almost always significantly lower than the best-of-judgement figure.

Should I use a tax professional for an amendment?

For simple self-amendments (missed rent relief, found WHT credit note, arithmetic error), you can handle the process yourself. For formal objections to assessments — especially where large amounts are at stake, expenses have been disallowed, or the tax authority has raised a best-of-judgement assessment — professional representation significantly improves your chances of a favourable outcome. Tax practitioners understand local State IRS procedures and negotiation norms. Find one through our Tax Professional Directory.