The supplier may not be VAT-registered (e.g., small vendor under THB 1.8M turnover), in which case they cannot issue a tax invoice, only an ordinary receipt.

A tax invoice is the primary document required by the Thai Revenue Department for a VAT registrant to claim input VAT and to substantiate the deductibility of an expense for Corporate Income Tax (CIT).

When goods are purchased without a proper tax invoice, it poses significant challenges for the company’s tax compliance, particularly regarding VAT credits and also the deductibility of the expense.

General Criteria CIT Deductibility

The expense might still be deductible for CIT if:
• the company can prove it was genuinely incurred for business purposes, and
• supported by other credible evidence, for example signed copies of the vendor’s ID card attached to the receipt.

However, it will likely face scrutiny on a case-to-case basis.

Documentation Needed For CIT Deduction

• Ordinary receipt that clearly states the vendor’s name, date, type of goods, and amount.
• Copy of vendor’s ID card, signed by vendor.
• Proof of payment (bank transfer slip, credit card statement, or company’s internal cash voucher).
• Further backup:
• Internal memo or approval explaining the business necessity of the purchase, if needed.
• Delivery note or goods received note as evidence of goods actually being received.

References

• Thai Revenue Code, Section 65 ter (3) (General expense deductibility)
• Thai Revenue Code, Section 82/5 (Requirements for a tax invoice)
• Thai Revenue Code, Section 82/3 (Input VAT deduction conditions)
• Notification of the Director-General of the Revenue Department (regarding acceptable evidence for expenses where no tax invoice is required from the seller).