How to file a personal income
tax return in Thailand

Learn how to file your personal income tax return in Thailand easily. This article will show you everything you need to prepare for your tax filing and take you through each filing process step. 

Juraj Micka

Compared to other countries, such as the UK or the USA, filing a personal tax return in Thailand is surprisingly easy. It only takes a few minutes (provided you have been doing the calculations all along using the Thailand tax calculator). Even if you haven’t, it’s still a relatively straightforward process that consists of three steps:

  1. Preparing your numbers & documents
  2. Choosing the filing method
  3. Filing your tax return

1. Preparing your numbers & documents

To get started, you will only need a couple of essential numbers and documents. Let’s start with the documents – you will need:

  • Tax ID (you got it when first started working as all employees need to have one)
  • Employer’s taxpayer identification number
  • Withholding tax certificates (the Revenue Department usually requests these in case of a tax refund)
    • Form BIS 50 provided by your employer if you are employed (or invoices if self-employed)
    • Certificate of Personal Health Insurance Premium for Income Tax Deduction from health insurance company
    • From your banks if you have savings accounts (usually the tax is withheld if the accrued interest exceeds 20,000 THB, but this only applies to Thais, foreigners are taxed on any interest right away)
    • Other certificates for other deductions such as life insurance

There might be other documents required based on your personal situation, but those listed above should be sufficient for most.

Now onto the numbers. If you haven’t calculated them yet, I recommend first downloading the tax calculator and going through the instructions on filling it in. Once you are done, you will be using the following numbers from the calculator:

  • Total income (employment and all other sources of income combined)
  • Withholding tax
  • Social security contributions
  • Deductions & allowances (depends on your scenario, see all available deductions here)

2. Four ways to file your tax return in Thailand

You have four options for filing your tax return in Thailand. Let’s look at them in detail:

Your employer will do it for you

The easiest way is to let your employer handle it for you. Most companies offer this service to their employees free of charge. The process is usually handled by the HR staff and requires no effort from your side.

Do it yourself

If you like to have the utmost control over your finances, you will want to file your personal income tax return by yourself. You have three equivalent options here. You can do it using:

The RD e-filing website (best for Thais)

The official government website comes in Thai only, making it a perfect choice for locals. If you don’t read nor speak Thai and still want to use it, there’s a way – you can use the “Translation into English” feature in Google Chrome/MS Edge or other browsers. The only catch is that some buttons don’t always translate, so you might require some assistance along the way.

Besides the ability to file your return, you will be able to view your previous filings and receipts on the website. You will need those documents later when, for example, renewing your work permit etc.

Visit website

The RDSmartTax app (best for expats)

By far, the easiest and foreigner-friendly way to file your personal income tax return is by using the government smartphone app. It’s available for both iOS and Android and has been reliable in the past. Unlike the website, this app comes in English, which makes it the best option for expats.

The app and the website are essentially just two different interfaces of the same system, and they will most likely be the two resources you will use most. I use the app for tax filing and the website for viewing or downloading previous filings whenever needed.

Visit website / download the app

Paper filing

Lastly, there’s a paper filing. I don’t know why anyone would want to do it, but you can also file your taxes the old-fashioned way using a paper and mailing it in. I have personally never done it this way, so this is where my advice ends.

3. Filing your tax return using the app

Okay, with your numbers and supporting documents ready, you can now file your tax return. We will use the mobile app to break down the individual steps and demonstrate the process.

*If you have never used the RD website, you will first have to create an account where login credentials are your tax ID and the chosen password.


  • Step 1: Log in to your E-filing account

  • Step 2: Tap on Tax Filing

  • Step 3: Tap on the P.N.D. 91 button

  • Step 4: Toggle on allowances/deductions that apply

  • Step 5: Toggle on allowances/deductions that apply

  • Step 6: Toggle on allowances/deductions that apply

  • Step 7: Enter your income, withholding tax and employer’s tax ID

  • Step 8: Enter your social security contributions, health insurance premium (the last field is just last year’s tax break)

  • Step 9: The app calculates your tax due

  • Step 10: Tap confirm

  • Step 11: Review the entered numbers and final calculation

  • Step 12: Save the summary of your filing. If there’s any payment due, you will see a payment deadline

  • Step 13: An overview of payment methods

    Congratulations, you have successfully filed your tax return. 🎉 At this point, you will have either overpaid, underpaid or paid your tax precisely. Because the last outcome is quite rare, we will now quickly go through how to deal with the first two scenarios.

    Paying off your remaining tax balance

    In case of a positive balance (meaning you have underpaid your tax), you will have to pay off the rest of your tax bill. The deadline for your payment is stated on the summary page, but it’s usually the end of June. Below the summary, the app then offers multiple ways to pay the remaining tax. Those are:

    • ATM
    • Telebanking
    • Internet banking
    • Mobile banking
    • Counter service/pay at post

    Getting a tax refund

    If you have overpaid, you will get your money back in the form of a tax refund. You will need to keep an eye on the app to see any messages from the RD. Usually, when you are owed money, the RD will ask for your supporting documents (that’s why you need to have them ready). You can then upload and submit these through the apps for their check. If everything adds up, you will receive your refund.

    The rules around getting the tax refund change over time, so the actual payment method will vary. In 2020, for example, those with a tax refund received a Bangkok Bank check that had to be cashed in in their bank. But instead of paying in cash, they were issuing a cash card.


    What if I made a mistake?

    Mistakes happen, but fortunately, it’s easy to fix them. You will need to go through the whole process again and resubmit your return (even if it’s after the deadline). The RD will be notified of your resubmission and will update your status in the app accordingly.

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