How to declare Thailand income tax by online


Welcome back to my blog!, Today, I would like to explain how to declare your income tax online. If you are working in Thailand and you pay income tax every month same as me, you need to file a tax declaration form. This process is mandatory for all people, either Thai or foreigners in Thailand As long as you have source of income in Thailand, you must do it.


Submission Deadline

January 1st to March 31 (In 2021, period is extended until June 30th )
Normally you have to file a tax declaration for previous year between January to March. However this year, the government extended the submission due so you still have one month more to fulfill your duty.

Document to prepare

  • Por Ngor Dor1
  • Pay slip in tax year
  • Proof for income tax deduction (if any.)     
Por Ngor Dor1 is withholding tax slip or so called W2 form in U.S. The company or organization you belong shall provide this document to you early January. If not yet, please ask HR or payroll staff in your organization. In addiction to this, if you have document which can be used for tax deduction please prepare also.
All such evidences needs to be attached to online application so please scan and make it as PDF format in advance.

Online submission process.

Access Revenue Department website
Click below address.
Register and Login
If you already registered by the website before, you can login with your TAX ID number and password. IN case you visit this site first time, you need to register with Tax ID number by clicking “register” button in the middle.


Click “Foreigner”


Although you clicked “Foreigner” in previous page, Website does not support English translation so please check my guide and input your information in the field. Date of birth is to be recorded using Buddhist year (bbbb means Buddhist year) so you can convert in this way.


Western calendar year + 543 = Buddhist calendar year.
eg.  1990 + 543 = 2533 in Buddhist calendar year


As you input each item, you will know that the pull down choice for suffix is all in English but country is all Thai so you have select your country in Thai not in English…. Why Thai government! LOL. For this, please google your country name in Thai then copy and paste Thai county name in the field on website so you can select your country in Thai. After completing all input, click next page.

After this you have to register your information such as your address and password but sorry I cannot go to next page since I already registered several years ago. So readers please complete by yourself! Sorry for inconvenience.


Once you complete registration, please login into the application page.

Click next.
Check registered information
On first page, you will see your registered information. If all is correct, please click next. This time, we will use online form so also make sure that “online” is ticked for filing type.
Input marital status
If you are single like me, you can just click “single” and “regular” for filing status. Otherwise, you are required to input your spouse information in right side on the page. Once complete, please click next.
Input of type of income and deduction

In this page, you are required to input your source of income and deduction. If you are working in a company then not participating in any program or products that can be used for income tax deduction, you can just click “Income from employment” (top) in income source and Social security fund contribution in deduction side. In addition, your company might provide provident fund program to the employee. In such case, you better click on “Provident fund” (top) in deduction section.

In my case, I purchased Life insurance, SSF and SSFX in 2020 and and purchased some goods with VAT so I also click “Purchase of goods or services (from 23 Oct. 2020 – 31 Dec. 2020)” which is the program that Thai government practiced end of 2020. Up to 30,000 THB purchase of products and service during above period, purchased amount can be used for income tax deduction. Thai government sometimes enforces such law to promote general consumption. To apply for deduction, you will be in need of TAX invoice document from store or service provider to submit as proof.

Input information of “Por Ngor Dor1”

In this page, you are required to input your Income and withholding tax and your company’s TAX ID number from “Por Ngor Dor1”. After inputting all information, system will calculate the balance after expense deduction (up to 100,000THB) and you and your family’s basic deduction.

Depends on your marital and family status, items on the screen might differ.
Input amount for income tax deduction

This is last input section, you are asked to input the amount for tax income deduction. Screen shows items that I selected in the application. With completion of all amount input, system will show total of income tax deduction amount at the bottom. Once finished, please go to next page.

Confirm refund/additional payment amount

Based on all information you input in the application process, system shall calculate the adjustment amount in “No.20” above. If “over pay” you can request refund for the amount, while if the result shows “additional pay”, you need to pay income tax additionally.

Attach the documents

In last page, you also need to submit the document, Por Ngor Dor1 and the evidences for income tax deduction.

Check application status

Once you successfully submitted application, you can check the application status by below link.

หน้าหลัก | กรมสรรพากร - The Revenue Department (
กรมสรรพากร จัดเก็บภาษีทันสมัย ใส่ใจบริการ ยึดมั่นธรรมภิบาล เพื่อพัฒนาการเศรษฐกิจและสังคมไทย

Please input only capital letter for name filed above otherwise system shows that your data cannot be found.
You can easily check application progress by the department, once it reaches 4th icon, document for refund is already sent to your registered address. above 5th icon shows that refund process is complete. In my case, from online application to get refund, it took around one and half month. Processing period varies.
OK! that’s all for online application process for income tax declaration, thank you so much for following my guide and hope you succeeded. I will also make article how to get refund in bank and income tax deduction tips for this year. See you!