What to Do If You File Your Taxes Late After the Deadline

The tax filing deadline has passed… now what? Every year, the Revenue Department reminds taxpayers to file their taxes on time. However, sometimes life gets hectic and important matters like tax filing slip our minds. The Revenue Department allows individuals to file their personal income tax returns for the 2024 tax year (forms Por Ngor Dor 90 and 91) online through the D-MyTax system starting now until 8 April 2025. For paper filing at the Revenue Office, the deadline was 31 March 2025. If you missed the deadline and are worried about penalties or consequences for late filing or not filing at all, don’t panic. Today, we will guide you through the steps and what you need to do if you file late, so you can handle your tax matters properly and with peace of mind.

You can skip parts if it’s too long.

1. What to Do If You File Taxes Late

2. Cases When You Need to File Back Taxes

3. What Happens If You File Taxes Late

1. What to Do If You File Taxes Late

Filing personal income tax is an important responsibility for anyone earning above the required threshold. However, sometimes unforeseen circumstances prevent timely filing. The most important thing is to handle the situation as soon as possible to minimize any negative consequences. Let’s see what you should do if you file your taxes late.

Steps to Take When Filing Taxes Late

1. Prepare Your Documents

• Tax form PND 90 or PND 91, depending on your income type
• Income evidence documents such as withholding tax certificates (Form 50)
• Documents for tax deductions like life insurance payment certificates, donation receipts
• Copy of your ID card

2. Submit Tax Forms at the Revenue Office

• Since the deadline has passed, online filing is no longer available. You must submit a paper form in person at your local revenue office.
• Fill out the forms completely and accurately.

3. Pay Any Tax Due (If Applicable)

• If you owe tax, you must pay it along with any fines and surcharges (if any).
• Payments can be made at the revenue office or through designated channels.

4. Penalties and Surcharges

• Late filing penalties apply as per law, but you may be eligible for reductions.
• If tax is owed, surcharges will be charged at 1.5% per month of the unpaid tax amount.

5. Request for Penalty Relief (If Applicable)

• In some cases, you may request relief from penalties by submitting a petition to the tax authorities.

Valid reasons include unavoidable situations that prevented timely filing.

2. Cases When You Need to File Back Taxes

Filing income tax retroactively usually occurs when the taxpayer fails to submit the tax return or submits an incorrect tax return that does not reflect the actual situation. This may result from lack of knowledge, misunderstanding, or intentional tax evasion. The cases that may require retroactive income tax filing are as follows:

Did Not File a Tax Return

• If a taxpayer who meets the income threshold does not file a tax return at all, they will be required to file back taxes when discovered.

Filed an Incorrect Tax Return

• If a tax return is filed incorrectly, such as underreporting income or incorrectly claiming deductions, an amended return must be submitted to correct the information.

Notified by the Revenue Department

• If the Revenue Department discovers incorrect filing or unreported income, they will notify the taxpayer to file back taxes.

Additional Income

• If there is additional income not reported in the original tax filing, such as dividends received or income from the sale of assets, back taxes must be filed to declare the extra income.

3. What Happens If You File Taxes Late

Filing taxes late or missing the deadline is something many people may have experienced—whether due to complicated paperwork or misunderstandings about deadlines. However, neglecting to file taxes or filing late can lead to legal consequences and additional costs.

Penalties

• The Revenue Department will impose a penalty for late filing, which varies depending on how late the filing is and the type of tax.
• The maximum penalty is 2,000 Baht according to Section 35 of the Revenue Code, but it is possible to request a reduction.

Surcharge

• If there is tax owed, a surcharge of 1.5% per month on the unpaid tax amount must be paid.
• This surcharge is calculated from the due date until the date the tax is paid.

Credibility

• Filing taxes late may affect your credibility in financial transactions.
• It could impact your ability to obtain loans or conduct other transactions with government agencies.

Therefore, don’t forget to file your taxes on time to minimize the impact and hassle that may follow. The sooner you file and pay your taxes, the less penalty and surcharge you will have to pay. Also, keep your tax documents as proof. When planning your tax filing, don’t forget to plan your tax deductions as well. Get double benefits — both health coverage and tax deduction — with comprehensive health insurance from Muang Thai Life Assurance, covering medical expenses from 200,000 Baht up to 100 million Baht. Plus, you can claim a tax deduction on premiums up to 25,000 Baht.

For more information:

☑️ Call Tel. 1766, available 24/7.

☑️ Contact a life insurance agent.

• Please study the details of coverage, conditions, and exclusions before making a decision to purchase insurance.

Sources: Retrieved on 07/03/2025

🔖 Revenue Department

🔖 ThaiPBS

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