The deadline for submitting supplementary personal income tax returns is a common issue for accountants and individuals after completing their tax return but discovering errors in income, family deductions, withheld tax amounts, or taxpayer information. In practice, many businesses only discover mistakes when reviewing payroll records, comparing withholding tax documents, or when the tax authorities send a data reconciliation notice.
From an accounting perspective, understanding the deadline for filing supplementary personal income tax returns not only helps businesses protect the rights of their employees but also limits the risks of late payment penalties, administrative fines, and discrepancies in tax reports. According to the 2019 Tax Administration Law and regulations applicable until 2026, taxpayers are entitled to file supplementary returns multiple times, but only within the legally permitted timeframe.
This article will provide a detailed analysis of the deadline for submitting supplementary personal income tax returns, the required documents, how to process them using eTax and HTKK software, common accounting errors, and important notes to avoid penalties.
What is the deadline for submitting supplementary personal income tax returns?
According to Clause 1, Article 47 of the 2019 Law on Tax AdministrationTaxpayers have the right to submit supplementary tax returns whenever they discover errors in previously submitted returns. However, the deadline for submitting supplementary personal income tax returns is not indefinite.
Specifically, the deadline for submitting supplementary personal income tax returns is determined as follows:
- The erroneous declaration can be filed within 10 years from the deadline for submitting the tax return for the tax period in which the error occurred.
- The supplementary payment must be made before the tax authorities announce a decision to conduct an inspection or audit at the taxpayer's premises.
- If the tax authorities have already announced a decision to conduct an audit or inspection, taxpayers can still file supplementary returns, but will be subject to penalties if it increases the amount of tax payable.
For example: The company submitted its 2024 personal income tax return on March 31, 2025. In August 2026, the accountant discovered a missing withholding tax certificate for one employee, resulting in an overpayment of 12 million VND. This case is still within the deadline for submitting the supplementary personal income tax return, as less than 10 years have passed since the original deadline.
In practice, most tax adjustment filings are done within 1 to 3 years after tax settlement, as this is when accountants typically review data during corporate tax settlement or when employees request tax refunds.
Is it possible to submit supplementary personal income tax returns multiple times?
One of the most common questions is whether there is a limit on the number of times a person can file a supplementary personal income tax return.
The answer is no. The law does not limit the number of times an amendment can be filed. Accountants can file amendments multiple times if they continue to discover new errors.
For example:
- First time: Correcting errors in the employee's ID card number or tax identification number.
- Second time: Supplementing documents for dependent deductions.
- Third time: Adjusting the amount of tax deducted due to incorrect payroll entry.
However, each adjustment must be made within the deadline for submitting supplementary personal income tax returns and must be accompanied by complete explanatory documents. If the accountant repeatedly submits supplementary returns for the same period, the tax authorities may assess that the business does not have good control over its internal data.
Therefore, before submitting supplementary documents, the accountant should:
- Review all payroll records, personal income tax statements, and withholding certificates.
- Compare the data with the accounting software, payroll software, and the detailed ledger for account 3335.
- Double-check all personal deductions, dependent deductions, insurance, and tax exemptions.
These are common cases requiring supplementary personal income tax returns.
In the corporate accounting environment, the deadline for submitting supplementary personal income tax returns is often a concern when one of the following situations arises:
Error in taxable income
This is the most common mistake. Accountants might miss this:
- Year-end bonus.
- Irregular income.
- Taxable support.
- The benefits are in kind.
When errors are discovered, businesses need to adjust the tax return to accurately reflect actual income.
Incorrect dependent information
Many individuals register dependents late or lack supporting documentation. If a dependent is eligible but not yet claimed as a tax deduction, the accountant can absolutely submit supplementary documentation within the deadline for filing the supplementary personal income tax return to reduce the amount of tax payable.
Error in deducted tax
Some businesses enter incorrect deductible tax amounts on documents or on the tax return. Appendix 05-1/BK-QTT-TNCNIn that case, the figures on the final settlement will not match the data from the tax authorities.
Incorrect tax identification number or personal information
Entering incorrect tax identification numbers, citizen identification numbers, dates of birth, or residential addresses can lead to inaccurate tax return records. These errors need to be corrected promptly to avoid affecting tax refunds or deductions.
Businesses or individuals who self-declare their personal income tax and encounter difficulties in filing can refer to this information. tax accounting services Or contact MAN – Master Accountant Network for free support and advice!
Documents to prepare while still within the deadline for submitting supplementary personal income tax returns.
When errors are discovered and the deadline for submitting supplementary personal income tax returns is still within the specified period, the accountant needs to prepare all the necessary documents as required. A typical set of documents includes:
- Supplementary declaration form.
- Supplementary declaration form.
- The tax return has been adjusted.
- Relevant documents.
Supplementary declaration form
Businesses typically use Form 01/KHBS or the "Supplementary Declaration" function on HTKK/eTax. The declaration form must include:
- The previously declared target.
- New adjusted targets.
- The difference is either increasing or decreasing.
Supplementary Explanation
This is a very important document from an accounting perspective. The explanation should include the following:
- The cause of the error.
- Time of discovery.
- This affects the amount of tax payable.
- Basis for adjustment.
For example: Because the accountant had not received all the necessary documents for registering dependents of employee Nguyen Van A at the time of the 2025 tax settlement, the company did not calculate the corresponding family allowance deduction. Therefore, the company is now filing an amended tax return to adjust and reduce the amount of personal income tax payable.
Supporting documents
Depending on the specific case, the following documents may be required within the deadline for submitting supplementary personal income tax returns:
- Tax deduction certificate.
- Employment contract.
- Payroll.
- Dependent records.
- Income verification.
- Bank statement.
Accounting guidelines for determining the correct deadline for submitting supplementary personal income tax returns.
A common mistake is that accountants confuse the deadline for filing the final tax return with the deadline for submitting supplementary personal income tax returns.
For example:
- Businesses must submit their 2025 personal income tax returns no later than March 31, 2026.
- From April 1st, 2026, businesses will begin the deadline for submitting supplementary personal income tax returns.
- The deadline for making adjustments is March 31, 2036.
Accountants should create a separate tracking table for each fiscal year as follows:
| Settlement period | Initial deadline | The deadline has been extended. |
| 2024 | 31/03/2025 | 31/03/2035 |
| 2025 | 31/03/2026 | 31/03/2036 |
| 2026 | 31/03/2027 | 31/03/2037 |
Creating this tracking sheet helps accountants proactively check and avoid missing deadlines for submitting supplementary personal income tax returns.
How to submit supplementary documents via eTax
Currently, the most common method for submitting supplementary personal income tax returns is through the electronic tax portal. The steps are as follows:
- Step 1 – Log in to the system: Access the e-Tax portal using your tax identification number and registered account.
- Step 2: Select the tax period to be adjusted: Go to "Tax Filing," select "Supplementary Tax Return," and then select the correct tax period to be corrected.
- Step 3 – Re-enter the correct data: The accountant re-enters the items that need changing. The system will automatically calculate the difference between the old and new data.
- Step 4 – Digitally Sign and Submit the Document: After verification, the business digitally signs and submits the document. After successful submission, the accountant should save the electronic receipt, document code, XML file, and PDF version of the tax return. This serves as proof that the business submitted the supplementary personal income tax return within the deadline in case of any disputes later.
Declare the tax return on HTKK software and then submit it via eTax.
For businesses with a large workforce or complex data, the Tax Declaration System (HTKK) remains a more suitable tool. Process:
- Open the HTKK software.
- Choose the personal income tax return form.
- Select the status "Supplementary 1", "Supplementary 2", etc.
- Re-enter the correct data.
- Export the XML file.
- Log in to eTax to submit.
In practice, accountants should keep records of all supplementary tax returns for easy reference later, especially when the business is subject to a tax audit.
Is it possible to submit supplementary payments after the tax authorities have conducted an audit?
This is a situation many businesses face.
If the deadline for submitting supplementary personal income tax returns has not yet passed, but the tax authorities have already announced a decision to conduct an on-site audit, the accountant can still submit the adjustment documents. However:
- If the adjustments result in an increase in the amount of tax payable, the business may be subject to penalties and late payment fees.
- If the adjustment results in a reduction of tax payable or an increase in tax refund, the business is only allowed to make adjustments to the portion that has not yet been determined by the tax authorities.
After the tax authorities have issued their inspection report, businesses are only allowed to file supplementary declarations for items outside the scope of the inspection.
Therefore, accountants should proactively review their records before an audit is decided upon in order to make the most of the deadline for submitting supplementary personal income tax returns.
Penalties for late payment of additional fees.
If a business submits its supplementary personal income tax return after the deadline or incurs a tax shortfall, the penalties typically include:
Penalties for late filing:
- Delays of 1 to 30 days: fines of 2 to 5 million VND.
- Delays of 31 to 60 days: fines of 5 to 8 million VND.
- Delays of 61 to 90 days: fines ranging from 8 to 15 million VND.
- Over 90 days: a fine of 15 to 25 million VND will be imposed if any tax payable arises.
If the supplementary tax return increases the amount of tax payable, the business must pay additional late payment penalties at the following rates:
|
Late payment penalty = 0.03% x Amount of tax overdue x Number of days overdue. |
For example: The company's additional tax payment increased the personal income tax payable by 20 million VND, due to a delay of 120 days. Therefore, the additional tax amount to be paid is as follows:
|
Late payment penalty = 20,000,000 x 0.03% x 120 = 720,000 VND |
Therefore, the earlier a business detects and addresses issues within the deadline for filing supplementary personal income tax returns, the more it can minimize the resulting costs.
To avoid incurring unnecessary penalties, businesses can refer to the following: full-service accounting translation.
How should accountants record the payment of supplementary personal income tax?
When it is discovered that the deadline for submitting supplementary personal income tax returns has passed, businesses must not only amend the tax return but also adjust their accounting records.
In the case of an increase in the amount of tax payable
When determining that there is an outstanding personal income tax liability, record the additional tax obligation:
- Debit account 334
- Account number 3335
When making a payment:
- Debit account 3335
- There is account 111 or 112.
If late payment penalties apply:
- Debit account 811
- Account number 3339
Cases where the amount of tax payable is reduced
If, after adjustment, the business overpays, record a reduction in the obligation.
- Debt 3335
- There are 334
Overpaid taxes can be handled in two ways:
- Offset to the next period: Businesses automatically offset this overpaid tax against the personal income tax payable in the following months or quarters. This is the most common and simplest method in terms of procedure.
- Filing for a tax refund: If the business no longer has personal income tax payable (e.g., dissolution, cessation of operations) or the overpaid tax amount is too large, the business can file for a refund of the overpaid tax according to the regulations. Circular 80/2021/TT-BTC.
Conclusion and recommendations
The deadline for submitting supplementary personal income tax returns is up to 10 years, but this does not mean accountants can afford to be negligent. Allowing errors to accumulate for too long will lead to:
- It's difficult to find the original documents, especially when the former employee has left the company.
- Late payment penalties accumulated over many years can exceed the original tax amount.
- This creates a negative impression regarding compliance in the company's tax compliance profile.
Perform a personal income tax return review at least once at the end of each fiscal year before submitting your financial statements. If you have any doubts about the figures, please Contact MAN – Master Accountant Network now! To receive support in audits and reviews, ensuring the business remains secure before any inspection.
Contact information MAN – Master Accountant Network
- Address: No. 19A, Street 43, Tan Thuan Ward, Ho Chi Minh City
- Mobile/Zalo: 0903 963 163 – 0903 428 622
- Email: man@man.net.vn
Content production by: Mr. Le Hoang Tuyen – Founder & CEO MAN – Master Accountant Network, Vietnamese CPA Auditor with over 30 years of experience in Accounting, Auditing and Financial Consulting.
Answers to frequently asked questions regarding the deadline for submitting supplementary personal income tax returns.
Yes. The Tax Administration Law does not limit the number of times you can make supplementary payments. As long as you do it before the tax authorities announce a tax audit or inspection decision and it is still within the 10-year period.
The overpayment is not automatic. The tax authorities will record the overpaid amount in the system. Businesses have the option to offset the overpayment against the tax payable in subsequent periods or file a claim for a refund of the overpaid tax as per regulations.
Yes. Businesses are still responsible for adjusting the figures to reflect actual payments at that time. Making supplementary payments helps businesses clean up their books and avoid the risk of being subject to back taxes or administrative penalties during corporate tax settlement.
Filing supplementary tax returns is a legitimate right. However, if a business files supplementary returns too many times for the same tax period, or if the adjusted figures show unusual fluctuations, the tax authorities may take notice and include it in a priority review list. I submitted the first supplementary declaration but still found errors. Can I submit it a second or third time?
If an additional payment reduces the tax payable, will the money be refunded immediately?
If an employee left the company a long time ago and an error is discovered now, is the company required to pay the additional amount?
Does filing a supplementary tax return increase the risk of being audited?
