Construction Loan Interest Rates in Thailand: Fixed vs Floating in 2026

Construction Loan Interest Rates in Thailand for 2026

Construction loan interest rates are one of the first numbers to plan around before building a house in Isaan. The rate you get shapes your monthly payment for years, so it deserves attention before you sign a contract with a bank. Thailand’s central bank, the Bank of Thailand (BOT), held its policy rate at approximately 1.00 percent per year at the Monetary Policy Committee (MPC) meeting held on 24 June 2026, a unanimous decision (source: Bank of Thailand, corroborated by ThaiPublica). This policy rate is the base that commercial and state banks reference when setting their own lending rates.

The rate that actually appears in a loan contract is not the policy rate itself, but each bank’s MRR (minimum retail rate), adjusted up or down from that base. The Government Housing Bank (GHB), a state bank focused on home loans, lowered its MRR to approximately 6.145 percent per year, effective 4 March 2026, specifically to ease the burden on home borrowers (source: ThaiPublica). Major commercial banks, including Bangkok Bank, Krung Thai Bank, Kasikornbank and Siam Commercial Bank, had MRR figures in the range of roughly 6 to 7 percent per year as of 11 September 2026 (source: Infoquest).

These numbers shift every quarter depending on the economy and MPC decisions. Anyone about to apply for a loan to build in Korat or Roi Et should confirm the current rate directly with the bank before deciding, rather than relying on figures from an article or an advertisement. Each bank applies different discounts depending on the borrower’s profile, so the final number is always case by case.

Fixed-Rate Loans: What They Are and Who They Suit

A fixed-rate loan locks in a set interest rate for an initial period, commonly the first 1 to 3 years approximately, depending on each bank’s promotion at the time. After that period ends, the rate automatically switches to floating. Borrowers should read the contract carefully to see exactly how many years are fixed, and what formula applies afterward.

The advantage of a fixed rate is predictable monthly payments during the early period, unaffected by market swings. This suits borrowers with steady monthly income, such as government employees or salaried staff, because it makes budgeting easier during the period when the house is still under construction and payments have just begun.

The limitation is that once the fixed period ends, if market rates have risen, the monthly payment can jump noticeably. Borrowers who choose a fixed rate should set aside budget for year 2 or year 4 onward, and should never calculate their repayment capacity based on the first-year number alone.

Floating-Rate Loans: What They Are and Who They Suit

A floating rate is calculated as the bank’s MRR minus an agreed discount, commonly described as MRR minus x percent, often adjusted again after year 3 to MRR minus y percent. The exact discount varies by bank and by borrower profile. This means the rate can move up or down throughout the loan term, tracking changes in MRR.

The advantage is that if the BOT lowers its policy rate further in the future, banks tend to lower their MRR accordingly, and the borrower benefits immediately without needing to refinance. This suits borrowers who can tolerate some fluctuation and who have enough income buffer to absorb a rate increase in some periods.

The risk is that the monthly payment is not fixed. During a period when a borrower is repaying the loan while construction costs are still being paid, a sudden rate increase can strain the budget. Borrowers should calculate their repayment capacity at the highest plausible rate, not just the lowest rate shown in a brochure.

Comparing Construction Loan Interest Rates: Fixed vs Floating

When comparing construction loan interest rates between the two options, the main difference is payment certainty, not just the lowest headline number. A fixed rate offers peace of mind early on, while a floating rate offers a chance at a lower rate if market conditions cooperate. The right choice depends on each borrower’s own risk tolerance, not on trends or someone else’s advice.

For a house still under construction, the loan is usually disbursed in stages tied to construction progress, similar to a BOQ (bill of quantities, an itemized cost schedule) drawdown, rather than paid out in full on day one. Interest is charged only on the amount actually disbursed at each stage, not the full approved credit line. During this period the difference between fixed and floating has limited impact, since the disbursed amount is still small, but it becomes more significant once the house is finished and the full loan amount is being repaid.

Some borrowers mix both approaches, using a fixed rate during construction, then considering refinancing or renegotiating terms once the house is complete. This approach reduces the risk of a sudden rate jump while construction costs are still overlapping with loan repayment. It is worth discussing actual terms with a loan officer at each bank before deciding.

Factors to Consider Before Deciding, for a House in Isaan

Location affects some loan conditions. Houses in urban areas like Korat or Roi Et typically have clearer appraised values for land and structure than houses in more rural areas. Houses near Khao Yai or Pak Chong, often built as vacation homes, may be assessed by some banks under different terms and credit limits than a primary residence.

Actual construction time is also an important factor. A house that takes longer to build than planned means paying interest during the construction period for longer than estimated. Homeowners should build extra time into their interest cost calculations in advance, rather than calculating based on the fastest possible timeline.

A borrower’s income and existing debt affect both the approved credit line and the discount received on MRR. Borrowers with a good credit history and low existing debt usually receive a larger discount than an average borrower. Before applying, it is worth checking one’s own credit history and reducing unnecessary debt where possible.

How to Prepare Before Applying for a Construction Loan

Before applying, a borrower should have house plans and a BOQ (bill of quantities, an itemized construction cost estimate) ready from a contractor or home-building company. Most banks use this document to assess the loan amount, not just the land price alone. Having complete documentation from the start helps the approval process move faster.

It is worth comparing terms from at least 2 to 3 banks approximately, covering the fixed-period rate, the floating-period discount, and various fees, since each bank’s promotions change over time. Comparing several banks gives a clearer picture of the true cost over the full loan term. One note for foreigners: land in Thailand generally cannot be owned outright by a non-Thai national, which affects how a construction loan and the underlying land title, such as a chanote (the full land title deed), are structured.

As a home builder working across Isaan, OBILIS has found that homeowners who prepare house plans and a budget in advance tend to get loan approval more smoothly, with terms better suited to their financial situation. Planning interest costs alongside the construction plan from the start genuinely reduces the risk of budget overruns along the way.

If you want a figure for the house you actually have in mind, try the budget planner first, or contact us for an estimate based on your real plan and land.

Related reading: Land and Building Tax in Thailand: What New Homeowners Pay

Frequently Asked Questions

Is a fixed or floating rate better for building a house?

There is no single answer that is always better. It depends on each borrower’s risk tolerance and income stability. Someone who wants certainty in early monthly payments may prefer a fixed rate, while someone who can handle fluctuation and wants a chance at a lower rate as the market moves may prefer a floating rate.

What is the approximate construction loan interest rate right now?

MRR rates from major commercial banks and GHB were in the range of roughly 6 to 7 percent per year approximately, based on the most recent figures found as of September 2026 (source: ThaiPublica and Infoquest). The actual rate each borrower receives will be adjusted from this base depending on the bank’s conditions and the borrower’s profile.

When should someone building in Korat or Roi Et start applying for a loan?

It is best to contact a bank as soon as house plans and a BOQ are ready, before construction actually begins, since approval and staged disbursement take time. Starting early also leaves time to compare terms from several banks before signing a contract.