Corporate Tax: Extension Options Explained

Running out of time to file your corporate tax? Here are your extension options in Thailand.

 

Standard Deadlines

Paper Filing

• Deadline: 150 days after fiscal year-end
• For calendar year: May 29 (150 days from Dec 31)
• No extension available for paper filing

 

E-Filing

• Deadline: May 31 (for calendar year companies)
• Automatic extension: Built into e-filing system
• Extra days: Approximately 2 days beyond paper deadline

 

Automatic E-Filing Extension

How It Works

When you file electronically, you automatically get until May 31:

• No application needed
• No approval required
• Just file online by May 31

 

Requirements

• Register for RD Smart Tax account
• Have digital signature
• Submit via e-filing portal

 

Benefits

• Extra 2 days vs. paper filing
• File from anywhere
• Immediate confirmation
• Faster processing

 

Special Circumstance Extensions

When You Can Request

Extensions beyond May 31 are rarely granted but possible for:

• Natural disasters affecting business
• Serious illness of key personnel
• Major system failures
• Government-ordered closures

 

How to Request

1. Submit written request to Revenue Department
2. Explain circumstances with supporting evidence
3. Propose new deadline (typically 30-60 days)
4. Wait for approval (not guaranteed)

 

Required Documentation

• Formal letter on company letterhead
• Evidence of circumstances (medical certificates, disaster reports, etc.)
• Explanation of why filing is impossible by deadline
• Proposed alternative deadline

 

Payment Extensions

Important Distinction

• Filing extension: More time to submit forms
• Payment extension: More time to pay tax owed

These are separate and payment extensions are harder to obtain.

 

Payment Deadline

• Same as filing deadline: May 31 (e-filing) or 150 days (paper)
• No automatic extension for payment
• Late payment penalty: 1.5% per month

 

Requesting Payment Extension

Rarely granted except for:

• Severe financial hardship
• Force majeure events
• Government-approved restructuring

 

Installment Payment Plans

Alternative to Extension

If you can't pay full amount by deadline:

Option: Request installment plan

• File return on time
• Pay partial amount
• Request to pay balance in installments

 

How to Request

1. File tax return by deadline
2. Pay what you can (minimum 25-50%)
3. Submit installment request
4. Propose payment schedule (typically 3-6 months)

 

Approval Factors

• Payment history
• Reason for inability to pay
• Proposed schedule
• Company financial situation

 

Penalties for Late Filing

Late Filing Penalty

• Amount: 1,000-2,000 THB
• Plus: 1.5% per month on unpaid tax

 

Late Payment Penalty

• Rate: 1.5% per month
• Compounds: Monthly
• No cap: Continues until paid

 

Example

• Tax owed: 500,000 THB
• 3 months late
• Late filing: 2,000 THB
• Late payment: 500,000 × 1.5% × 3 = 22,500 THB
• Total penalty: 24,500 THB

 

Strategic Planning

Don't Wait for Deadline

Best practice:

• Start preparation 3 months early
• Finalize 1 month before deadline
• File 1-2 weeks early
• Avoid last-minute rush

 

Use E-Filing

Even if you don't need the extension:

• Faster processing
• Immediate confirmation
• Digital record keeping
• Less hassle

 

Estimate and Pay Early

If you know you'll owe tax:

• Calculate estimate
• Pay before deadline
• File return when ready
• Avoid late payment penalties

 

BOI Company Considerations

Same Deadlines Apply

BOI companies follow same filing deadlines as regular companies:

• 150 days (paper) or May 31 (e-filing)

 

Additional BOI Reports

Don't forget BOI annual report:

• Deadline: 90 days after fiscal year-end
• Separate from tax filing
• Must file both to maintain BOI status

 

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Related Service: Accounting & Tax Compliance — We ensure timely filing, no extensions needed.