2026 Tax Calendar: What Must Companies File Each Month?

Companies in Thailand must file withholding tax and VAT on a monthly basis. The main forms include P.N.D.1 (payroll withholding tax), P.N.D.3 and P.N.D.53 (withholding taxfor wages/service fees), and P.P.30 (value added tax). These are generally due by the 7th or 15th of the following month. In addition, Social Security contributions must also be submitted every month.

 

What taxes must companies file every month?

• P.N.D.1: Withholding tax on employee salaries. Read more about calculation and document generation >> Payroll Software for Automatic P.N.D.1 and 50 Tawi Documents

• P.N.D.3: Withholding tax when paying individuals, such as service fees, rent, or freelance fees.

• P.N.D.53: Withholding tax when paying juristic persons, such as vendor or partner companies.

• P.P.30: Value Added Tax (VAT) return summarizing output and input VAT for that month.

 

Monthly Tax Filing Deadline Summary

The filing deadlines for P.N.D.1, P.N.D.3, P.N.D.53, and P.P.30 follow the same rule: by the 7th of the following month for paper filing, or by the 15th for online filing. If the 7th or 15th falls on a weekend or public holiday, the deadline is automatically moved to the next business day.

 

 

Note: The above deadlines follow general Revenue Department practice. In some years, special deadline extensions may be announced, so you should always check the latest notice from the Revenue Department.

 

Tax Forms Filed Only in Specific Cases

In addition to the four main forms that most companies file every month, there are two other forms used only for certain types of businesses or specific situations. Not every company needs to file them:

• P.T.40 (Specific Business Tax) — used for businesses specifically designated by law, such as banks, financial institutions, real estate trading businesses, and pawnshops.

• P.N.D.54 — used when a company pays certain types of income to a foreign juristic person that does not carry on business in Thailand (under Section 70 of the Revenue Code), such as royalties or interest paid to an overseas parent company.

Both of these forms follow the same filing deadlines as the main forms: by the 7th of the following month for paper filing, or by the 15th for online filing (with the same holiday adjustment rules shown in the table above).

 

Other Non-Tax Obligations Submitted in the Same Period

In addition to the tax forms above, companies must also submit monthly Social Security contributions for both employers and employees to the Social Security Office by the 15th of the following month. Many companies therefore include this step in the same payroll closing cycle as P.N.D.1 filing.

 

Taxes Filed Annually, Not Monthly

Apart from monthly taxes, companies also have annual or half-year tax obligations that are not part of the monthly calendar but should still be planned in advance, such as:

• P.N.D.50: Annual corporate income tax return, due within 150 days after the end of the accounting period.

• P.N.D.51: Half-year corporate income tax return, due within 2 months after the end of the first half of the accounting period.

• Withholding tax certificate (50 Tawi): issued to employees and vendors for their annual tax filing.

 

Tips to Avoid Missing Monthly Tax Deadlines

1. Prepare an annual tax calendar in advance and clearly note the due date for each form.

2. Use payroll software that automatically calculates and generates tax documents to reduce the risk of errors and late filing. Read more >> Payroll Software for Automatic Social Security and Tax Calculations

3. Set reminder alerts in advance each month for both the accounting team and HR.

4. Assign a clear person responsible for each filing type to avoid confusion about who files what.

 

Summary: 2026 Tax Calendar — What Must Companies File Each Month?

Companies generally need to file four main tax forms every month: P.N.D.1, P.N.D.3, P.N.D.53, and P.P.30. These are usually due on the 7th or 15th of the following month, together with Social Security contribution submissions in the same cycle. There are also annual filings such as P.N.D.50 and P.N.D.51 that should be planned separately from the monthly calendar. Preparing a tax calendar in advance and using automatic calculation tools can greatly reduce the risk of late filing or calculation errors.

 

Frequently Asked Questions About Tax Filing

What happens if tax filing is submitted after the deadline? 

There may be penalties and surcharges as prescribed by the Revenue Department. The amount depends on the tax type and the length of the delay, so deadlines should be checked carefully every month.

 

What is the difference between P.N.D.3 and P.N.D.53? 

P.N.D.3 is used for withholding tax paid to individuals, while P.N.D.53 is used for payments to juristic persons such as vendor companies.

 

If a company has no withholding tax items in that month, does it still need to file? 

As a general practice, if there are no withholding tax items in that month, a nil return may not be required. However, you should confirm the latest conditions with the Revenue Department or your accounting team, as some cases may have specific requirements.

 

How is online tax filing different from paper filing? 

Online filing through the Revenue Department system often receives an extended deadline compared with paper filing, giving companies more time to prepare data.

 

When should a newly established SME start filing monthly taxes? 

In general, withholding tax filing starts from the first month in which the business has taxable withholding items, such as paying employee salaries or service fees to individuals or juristic persons. Accounting and tax processes should be set up from the start of operations.

 

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• How Much Tax Is Payable on a THB 30,000 Salary? With Calculation Method 

• What Happens If You Miss a Tax Filing Deadline? What Should You Do? 

• How Is Progressive Tax Calculated? With Calculation Examples