Section 654 — Interest cap — 15% per annum
Statutory text (Thai original)
ท่านห้ามมิให้คิดดอกเบี้ยเกินร้อยละสิบห้าต่อปี ถ้าในสัญญากำหนดดอกเบี้ยเกินกว่านั้น ก็ให้ลดลงมาเป็นร้อยละสิบห้าต่อปี
Verbatim from the Royal Gazette / Office of the Council of State
English translation
Interest shall not exceed 15% per year; when a higher rate of interest is fixed by the contract, it shall be reduced to 15% per year.
This English translation is provided for reference only and has not yet been firm-verified — always rely on the Thai original.
Firm annotation
Section 654 caps private-party interest at 15% per annum. The cap is mandatory — parties cannot contract around it. Two important exceptions: (1) licensed financial institutions (banks, regulated NBFIs) operate under the Bank of Thailand's separate interest framework, often higher; (2) commercial loans between business entities have the same 15% cap unless one party is a licensed financial institution. The Act on Loans of Money Carrying Interest Beyond the Permitted Rate (B.E. 2475) makes charging interest above 15% a criminal offence punishable by up to 2 years imprisonment.